Category Archives: Metaphysics

No, science does not provide all the answers to the big questions

From time to time a famous scientist allows himself (in my experience it’s always a man) to write nonchalantly about something of which he demonstrably has only a superficial grasp: philosophy. The list of offenders is a long one, and it includes Lawrence Krauss, Neil deGrasse Tyson, and Stephen Hawking, among several others. (Fortunately, there are also exceptions, scientists who value a constructive intercourse with the humanities, like Sean Carroll.) The latest entry in this dubious pantheon is Peter Atkins, who recently published a sloppy essay in the otherwise excellent Aeon magazine entitled “Why it’s only science that can answer all the big questions.” Oh boy.


Atkins begins by telling us that there are two fundamental kinds of “big questions”:


“One class consists of invented questions that are often based on unwarranted extrapolations of human experience. They typically include questions of purpose and worries about the annihilation of the self, such as Why are we here? and What are the attributes of the soul? They are not real questions, because they are not based on evidence. … Most questions of this class are a waste of time; and because they are not open to rational discourse, at worst they are resolved only by resort to the sword, the bomb or the flame. … The second class of big questions concerns features of the Universe for which there is evidence other than wish-fulfilling speculation and the stimulation provided by the study of sacred texts. … These are all real big questions and, in my view, are open to scientific elucidation.”


This is not news, of course, at all. David Hume — one of my favorite philosophers — made essentially the same argument back in the 18th century, in his case rejecting what he saw as the waste of time associated with the Scholastic metaphysics that had prevailed throughout the Middle Ages:


“If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.” (An Enquiry Concerning Human Understanding)


With all due respect to Hume, it’s a good thing people didn’t follow his advice, or we would have lost his very own Enquiry Concerning Human Understanding, since that book doesn’t contain any abstract reasoning concerning quantity or number, nor does it contain any experimental reasoning concerning matter of fact. And yet, it is — justly — considered to be one of the most important works of modern philosophy.


Atkins apparently realizes that he may come across as a bit too facile, since he acknowledges that he is defining the big questions precisely as those that science can answer, turning then around to “demonstrate” that science is the only discipline equipped to answer such questions. As he drily puts it when considering the obvious charge of circularity: “that might be so.” Which doesn’t stop him from proceeding as if it were not so.


Atkins tells us that science is getting ready to tackle what he considers the next three big questions: How did the Universe begin? How did matter in the Universe become alive? and How did living matter become self-conscious?


I have no doubt, as a scientist, that those are, indeed, scientific questions. I’m slightly more skeptical, as a philosopher, that science will actually be able to come up with answers. Fundamental physics, after more than a century of uninterrupted success, seems to have entered a period of navel gazing where speculation (admittedly mathematically informed speculation) is poised to replace empirical evidence. So we shall see if and when we’ll actually get a “theory of everything,” and whether that theory will in fact be able to tell us how the universe began from “nothing” (there is some doubt that it will).


Regarding the second question, the origin of life, theories have been piling up for several centuries now, and yet we don’t seem to be particularly close to a resolution just yet. I’m certainly not arguing that it isn’t possible, but it’s a very, very difficult problem, for the simple reason that a lot of the historical traces have been lost. No geological strata survive from the time when the primordial earth was home to the first living organisms, meaning that researchers on the origin of life are like detectives who already know the smoking gun isn’t going to be found. At best, they’ll have to rely on circumstantial evidence. Even should we be able to produce life artificially in the laboratory that would not solve the problem, since it wouldn’t mean that life on our planet actually followed anything like that particular causal path.


As for consciousness, I remain convinced that the problem is indeed biological in nature, and that therefore developmental, evolutionary, and neuro-biology are the disciplines best positioned to find a solution. But at the moment nobody seems to have much of a clue, and common talk of the brain being a computer is finally beginning to be understood as the shaky and very likely misleading analogy that is.


So, yes, if any of those three big questions are going to be answered, the answer will be a scientific one. But what about other questions that arguably just as big (or, for most of us, even bigger)? Here Atkins shifts into full scientistic mode:


“I see no reason why the scientific method cannot be used to answer, or at least illuminate, Socrates’ question ‘How should we live?’ by appealing to those currently semi-sciences (the social sciences) including anthropology, ethology, psychology and economics.”


Please notice a number of interesting and revealing things about this sentence. First, Atkins is making the time-honored argument from personal incredulity: “I see no reason why…” Which, of course, is not an argument at all, but an elementary logical fallacy. Second, he is seriously hedging his bets when he immediately qualifies his initial statement: “or at least illuminate…” Ah, well, but philosophers since the Pre-Socratics have understood that empirical evidence (i.e., “science”) can illuminate philosophical questions. However, that’s a far more modest claim than the notion that science can actually answer those questions. Third, Atkins can’t help himself but deliver a contemptuous dig at the “semi-sciences.” This attitude, common among physicists, reflects a naive understanding of the philosophy of science, according to which physics is the (self-professed) “queen” of the sciences, and every other field will achieve full scientific status only when it will finally evolve into something that looks like physics. But an increasingly common view in philosophy is that there actually is a fundamental disunity of science, that “science” is only a loosely defined family resemblance term, reflecting the fact that each science has its own goals, methods, and internal standards, and that there is no universal yardstick to be appealed to in order to make comparative judgments of quality.


Going back to philosophy, the question of “how should I live?” admits of a large number of reasonable (and a lot of unreasonable!) answers, given the very same facts about the universe and human nature. It isn’t so much a question to be answered, as to be explored and clarified. Indeed, this is arguably what most fundamentally distinguishes science from philosophy.
One of my recent morning meditations is pertinent here. It begins with a quote by the Stoic philosopher Epictetus, who says in Discourses II, 11.13:


“Here you have philosophy’s starting point: we find that people cannot agree among themselves, and we go in search of the source of their disagreement.”


As I argue in the podcast episode, there are two broad sources of disagreement among human beings: factual and conceptual. If you and I disagree about, say, the number of moons orbiting around the planet Saturn, one of us is wrong, possibly both. There is a matter of fact about the issue, and we can find out the answer by asking an astronomer. Or more simply by doing a web search. If disagreement remains after that, then one of us is more than a bit obtuse.


The second kind of disagreement concerns how to think about facts, actions, and values. Here the facts are relevant, but insufficient to settle the dispute. Let’s say we have different opinions about the permissibility of assisted suicide. Certain empirical facts are going to be pertinent to the discussion, like information about how the procedure is going to be implemented, what safeguards there may be to avoid abuses, and so forth. But even if we agree on the facts, we may still disagree on the crucial issue: is assisted suicide morally permissible?


That’s the difference between science and philosophy, and why Epictetus says that philosophy begins with the search for why people disagree on things. Notoriously, philosophy does not necessarily settle such disagreements. The joke in philosophy departments is that our profession’s slogan is: “Philosophy: we have all the questions!” But what philosophy does, by means of careful analysis and reasoned argument, is to help us clarify why, exactly, we disagree. That is of huge help to people of good will who wish to honestly pursue discussions in search of better ways to conduct their lives. Atkins may want to take notice.

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Does the universe suffer from multiple personalities disorder?

I am the sort of rare philosopher who is somewhat skeptical of metaphysics. For instance, I recently wrote that I don’t think there is such thing as metaphysical necessity or impossibility, because those two categories are exhaustively covered by physics and logic: something is either physically or logically impossible / necessary. But if there is something that really makes my bullshit detector go up to red alert when it comes to metaphysical claims is the increasingly popular idea of panpsychism.


There are a number of versions of it (we will encounter a couple below), but essentially the notion is that consciousness is not — as biologists and neuroscientists would understand it — a highly evolved trait present only in human beings and, to a lesser extent, in other species with sufficiently complex brains. On the contrary, panpsychists think that it is an elemental property of the universe, like mass, or the spin of a particle, and is therefore present everywhere.


Needless to say, there is not a shred of empirical evidence that panpsychism is a correct description of the world, and the notion, in modern metaphysics, is tightly linked to the solution of an entirely made up (in my opinion) problem in philosophy of mind: some philosophers, like my New York University colleague David Chalmers, just can’t imagine how a mass of meat, electrical signals and chemicals (i.e., your brain) can possibly produce the first-person experience we all commonly have when we see red (literally, as in the color), or experience sexual pleasure, or think and feel anything at all.


Chalmers calls this the “hard problem” of consciousness, and I have argued that there is no such thing. Consciousness has not, yet, been understood by science, but there is no reason in principle why it couldn’t. It’s “hard” only in the sense that it requires a hell of a lot of imaginative empirical work.


The fact is that people like Chalmers find themselves in a pickle. Since they maintain that consciousness is a problem irreducible to the methods of science, they have to postulate some sort of dualism, i.e., a radical, qualitative separation between what regular matter does and what thinking matter does. The most famous dualist was Descartes, who thought that there are actually two different kinds of matter: res extensa and res cogitans (this is called substance dualism).


This sort of dualism has gone, thankfully, out of fashion in philosophy, only to be replaced by a milder (but I think equally untenable, in the form in which it is usually presented) type, known as property dualism. Property dualists like Chalmers argue that when matter (the same matter, not two different kinds as hypothesized by Descartes) is organized in a certain complex manner, then consciousness somehow emerges. This is problematic because nobody seems to have a clue about what emergence means in this case, or how to cash it out as an actual explanation of consciousness. It’s sophisticated hand waving, but hand waving nonetheless.


Enter panpsychism. Chalmers and others have figured out that this very old notion (it is found in a number of cultures across the globe, for instance in Stoic philosophy in the West) can be couched in modern philo-scientific jargon and made to do the work to solve the hard problem. Indeed, for a panpsychist, in a sense, the hard problem dissolves into a non-problem, because consciousness does not have to emerge from certain organizational patterns of matter, since it is a foundational property of matter itself. It’s consciousness all the way down, so to speak.


The idea is elegant an appealing. And I assure you that, as a modern Stoic practitioner, I would love for it to be true! But it is ad hoc, meaning that the only reason to believe it, so far, is that it solves an artificial problem created by philosophers of mind themselves. There is no empirical evidence or independent theoretical support (say, from biology, or fundamental physics) for us to believe it.


Which is why we now turn to a recent essay by Bernardo Kastrup, Adam Crabtree, and Edward Kelley, entitled “Could multiple personality disorder explain life, the universe and everything?” Yeah, you read the title right (and did you notice the reference to the brilliant Hitchhiker’s Guide to the Galaxy?) The article, published over at the Scientific American blogs, is a lay summary of a technical paper that I honestly can’t believe passed peer review: The universe is consciousness, which appeared in the Journal of Consciousness Studies (David Chalmers is on the advisory editorial board, tough that doesn’t mean there is any direct connection between him and the paper).


Before I get to the crazy part of Kastrup and colleagues’ article, let me talk about the bits where I agree with the authors. First off, multiple personality disorder, or as it is now known, dissociative identity disorder (DID), is real, and these authors are credentialed experts in that field. I am, therefore, not questioning what they say about the disorder itself.


People affected by DID switch between a number of alternative personalities, each characterized by its own distinctive behavior. Recent research has shown that there are clear neural correlates to each “alter.” For instance, a woman with DID exhibited some alters that claimed to be blind, even though there was nothing wrong with her optic nerve or any other part of her visual system. Using EEGs, researchers were able to confirm that the component of the woman’s brain activity normally associated with sight was, in fact, not present whenever one of her blind alters was in control. By contrast, when a sighted alter reasserted control, the usual brain activity returned. So the phenomenon is real, with a clear and demonstrable biological underpinning.


I also agree with Kastrup and colleagues’ criticism of standard versions of panpsychism. Specifically, they call the sort of panpsychism I described above “constitutive panpsychism” and write:


“Constitutive panpsychism has a critical problem of its own: there is arguably no coherent, non-magical way in which lower-level subjective points of view — such as those of subatomic particles or neurons in the brain, if they have these points of view — could combine to form higher-level subjective points of view, such as yours and ours. This is called the combination problem and it appears just as insoluble as the hard problem of consciousness.”


Yup, exactly.


Kastrup and colleagues then move to something called “cosmopsychism,” which is the idea that consciousness is indeed spread throughout the universe, but it isn’t particulate (i.e., present in bits and pieces in particles, molecules, rocks, neurons, and so forth) but rather one whole thing. This is really the old fashioned philosophical notion of idealism: there is only one, universal, consciousness.


But cosmopsychism also is no slam dunk:


“You don’t need to be a philosopher to realize the obvious problem with this idea: people have private, separate fields of experience. We can’t normally read your thoughts and, presumably, neither can you read ours. Moreover, we are not normally aware of what’s going on across the universe and, presumably, neither are you. So, for idealism to be tenable, one must explain — at least in principle — how one universal consciousness gives rise to multiple, private but concurrently conscious centers of cognition, each with a distinct personality and sense of identity.”


I think you know where this is going, right? Let us have Kastrup and colleagues tell us explicitly:
“We know empirically from DID that consciousness can give rise to many operationally distinct centers of concurrent experience, each with its own personality and sense of identity. Therefore, if something analogous to DID happens at a universal level, the one universal consciousness could, as a result, give rise to many alters with private inner lives like yours and ours. As such, we may all be alters — dissociated personalities — of universal consciousness. Moreover, there is something dissociative processes look like in the brain of a patient with DID. So, if some form of universal-level DID happens, the alters of universal consciousness must also have an extrinsic appearance. We posit that this appearance is life itself: metabolizing organisms are simply what universal-level dissociative processes look like.”


Holy crap. So we are now positing that the entire universe “suffers” from a multiple personality disorder because we need to solve a non-problem that we created ourselves out of stubbornly postulating that there is something special and quasi-magical about consciousness. And of course, all of this without either a modicum of empirical evidence or any serious theoretical reason (again, from either biology or fundamental physics) to back it up!


(Moreover, if the universe were suffering from DID and I were one of the alters, shouldn’t I perceive myself as a coherent entity looking out to the whole universe, just like human DID patients see the world around them from a standpoint of unitary consciousness, no matter which alter is in control?)


No my friends. I think it far more reasonable to take consciousness at face value. It’s a biological process (like photosynthesis, say), that evolved in certain groups of the phylum Animalia (but not in plants, fungi, bacteria, and the like) with a sufficiently complex brain. We do not know how it works in detail, though we are beginning to map its neural correlates. We also don’t know why consciousness was favored by natural selection (we infer that it must have been because the necessary brain structures are metabolically very costly), though there are hypotheses out there (it may have to do with our ability to create mental representations).


Let me be clear about one thing here: panpsychism, property dualism, and even substance dualism aren’t crazy ideas. They are not logically inconsistent or anything like that. But they are not consistent with everything we know from the natural sciences at this point. And if I have to choose between that knowledge and made up notions like the ones we have considered here, I’m whipping up my Occam razor and mercilessly slash through the whole shebang. At this point in time, the razor will surely cut down panpsychism. In the future, we’ll see, fate permitting.

Once more: is there such a thing as metaphysical necessity?

Some philosophers distinguish among three classes of necessary (or, conversely, impossible) things: (i) physical necessities (and impossibilities), meaning things that are going to happen (or can never happen) because of the ways the laws of physics are; (ii) logical necessities (and impossibilities), that is things that are true (or impossible) because of the laws of logic; and (iii) metaphysical necessities (and impossibilities), meaning things that are the case (or can never be the case) because of…? Yeah, the latter is the problematic one. Nobody doubts the existence of the laws of physics (though some philosophers reject that kind of talk and prefer to think in terms of causal regularities). Some people think that logical necessity / impossibility is actually the result of human constructs, since one can adopt different kinds of logic, but this is controversial. And then there is a small number of philosophers, the metaphysicians (sometimes they call themselves metaphysicists) who insist on a separate existence of the third category. And this is very controversial.

I wrote about metaphysical necessity / impossibility back in 2014, and then again (on the specific issue of “grounding”) in 2015. In both cases, I was rather skeptical of distinguishing metaphysical anything from either the physical or the logical realm. The way I saw it was this: logical necessity / impossibility > physical necessity / impossibility > contingency. That is, if something is, say, logically impossible, it is a fortiori physically impossible, and it can’t happen no matter what the specific circumstances. However, if something is happening, then it must be both physically and logically possible. And so forth. My argument in the past is that whatever examples of alleged metaphysical necessity / impossibility one would come up with it would either turn out to belong to the physical class or to the logical one, with nothing either in between or, somehow, above logic.

(For the rest of this discussion I will bracket two obvious questions: (a) where do the laws of physics come from? And (b) if logic is a human construct, then in what sense can we talk about logical necessity / impossibility? The only hint that I will give here is that I think the laws of physics themselves are a human construct, but they reflect a fundamental structure of reality. Something similar may be going on with logic. So there…)

Recently, a friend of mine and former student at CUNY’s Graduate Center (she has just successfully defended her thesis!) Antonella Mallozzi, has put out a very conveniently and nicely put together diagram to explore (and defend, in her case) the idea of metaphysical necessity as distinct from both the physical and the logical varieties. With permission from Antonella, I reproduce the diagram below, as it will guide us through the rest of the discussion. (Antonella has also guest edited a special issue on this topic for the journal Synthese, entitled “New directions in the epistemology of modality.” You can see her leading article here. I hear that my colleague Graham Priest, one of the best logicians out there, is also skeptical of the notion of metaphysical necessity, but I have purposely not read his paper, currently in print, so to be able to develop my own ideas.)

So what I’d like to do now is to go through each of Antonella’s possibilities for metaphysical necessity, briefly look at the examples that she presents, and see what happens. We will start with the right-center portion of her large circle (labelled “general metaphysical necessities”) and proceed counter-clockwise, one category and set of examples at a time.

(I) Logical, mathematical, and geometrical necessity (middle right of the large circle). Her examples here include “necessarily, everything is self-identical,” and: “necessarily, two plus two equals four.” As she points out, some philosophers are skeptical that these are examples of necessity, or that these statements are true, pointing to the existence of non-classical logics, non-euclidean geometries, etc. But I’m going to accept these examples as valid given certain axioms (classical logic, euclidean geometry, and so forth). You may disagree, of course, but as I mentioned above, I’m going to bracket any further discussion of this particular issue. Even if we do accept the examples, however, they fall squarely into the logical end of my continuum above, they are not distinctly metaphysical.

(II) Conceptual necessity (upper right of the large circle). Antonella here distinguishes between things that are epistemically necessary, but not metaphysically so (the part of the small conceptual circle that lies outside the largest one), and things that are both epistemically and metaphysically necessary (the little bit of the small conceptual circle that lies inside the largest one). An example of alleged epistemic (but not metaphysical) necessity is the following: “Julius” designates the inventor of the zip. It then is a priori (epistemically) necessary that if anyone invented the zip, Julius did. This seems to me a very weak sense of epistemically necessary, since it simply states that given that X is true, you better take X to be true. I think the use of the word “a priori” is misleading here, as it is obviously a contingent fact that Julius, and not someone else, invented the zip. More importantly, because of the latter possibility, even Antonella agrees that this is a case of metaphysical contingency.

What about metaphysical conceptual necessities? Antonella gives two examples: “necessarily, anything colored is extensive,” and “necessarily, there is a valley in between two mountains.” She also adds, however, that some people think these are logical, not distinctly metaphysical necessities. The case seems particularly clear for the second example: once one defines mountains as things that have peaks and are surrounded by valleys, then it is obviously logically necessary that if there are two mountains next to each other they will be separated by a valley. As far as the color example is concerned, it sounds to me like a case of contingency due to biology: colors are not “out there,” but rather the result of the interaction between physico-chemical properties of materials and the specific physiological and perceptual apparatus of a given organism. Perhaps one could say that more obviously intrinsic physical properties necessitate extension (meaning, something more than a geometrical point), but now that begins to look like a physical necessity, and even that is doubtful, if one accepts certain radical views of what actually constitutes the physical world.

(III) Grounding and mereology (top of the large circle). Antonella’s examples are “necessarily [P&Q] is grounded in [P], [Q],” and “necessarily, everything is a part of itself.” I have expressed my skepticism about the concept of grounding in metaphysics elsewhere (it’s pretty vague and slippery, and doesn’t seem to add anything), but Antonella herself comments that some people would consider these examples of logical necessity, not a distinctive metaphysical class.

(IV) Ethical-deontological necessities (upper left of the large circle). “Necessarily, violence is wrong.” Well, no. My ethics is a naturalistic one, so I don’t think there is anything that is necessary in that realm, at all. Ethics is very clearly, to me, a human construction, constrained by our biology as social animals capable of language, which means it isn’t entirely arbitrary, but also that there is nothing necessary about it. I am, most definitely, not a deontologist.

The last two classes of metaphysical necessities proposed by Antonella are important, because they fall into the circle labelled “distinctively metaphysical” (or Kripkean, in honor of the highly influential philosopher Saul Kripke, currently at CUNY’s Graduate Center). That is, in her mind these are the ones that cannot be reduced in any way to logical or physical necessities, so let’s pay particular attention.

(V) Causally-nomic (lower left of the large circle). Even Antonella readily admits that it is controversial whether anything at all falls into this group! Her examples include the laws of physics and chemistry, but it is an open question to say the least why the fundamental laws of physics are the way they are (those of chemistry, presumably, can be reduced to physics). It may be that they could not possibly have been different, because of the way the causal world is structured; or perhaps they could have been different, and the ones we observe are that way because of contingency. The first scenario would seem to be a case of physical necessity, while in the second scenario the only constraints would be imposed by logical impossibility and necessity. Again, no distinctive metaphysical criterion appears to be required.

(VI) Finally, we get to the most promising class, that of “de re,” a posteriori things that have their source in the fundamental nature, or essence, of things (lower part of the large circle). The pertinent examples are classics of the metaphysical literature: “necessarily, water is H2O,” or “necessarily, I could not have had different parents then the ones I actually have.” I am, however, utterly unconvinced. Water is H2O either as a matter of physical necessity (if the laws of physics could not have been otherwise) or it is a contingent fact about our universe (if the laws of physics could have been different). As for my parents, that seems an entirely contingent fact of our biology. For instance, if humans were a clonal species that reproduced by budding, “I” could have had a lot of different specific parents and still be “me” (not to mention that this example depends on one’s conception of personal identity, a controversial issue in its own right).

I guess this third look at metaphysical necessity / impossibility, despite Antonella’s brave and very clever attempt, still leaves me unmoved. I keep thinking that the logic > physics > contingency conceptual scheme is sufficient to account for all examples that have been presented, and that metaphysics is an artificial category situated between logic and physics: each alleged example of metaphysical necessity turns out, upon closer inspection, to be either a case of logical necessity, or one of physical necessity. But I remain open to be convinced otherwise. Stay tuned for a fourth possible look at the issue, a few years down the road!

Five big philosophical questions: my modest take

number 5

golden 3d number 5 isolated on white

An anonymous poster has recently published a short essay over at the Oxford University Press philosophy blog, entitled “5 great unsolved philosophical questions.” How could I possibly resist answering them, I ask you? Presumptuous, you might say. Well, no, that would be the case if I claimed that my answers are original, or clearly the right ones. I make no such claim, I am simply offering my informed opinion about them, in my dual role of a philosopher and scientist. Of course, I’m also totally right.

Before proceeding, I need to remind readers of my take on the nature of philosophical questions, and therefore of philosophy itself. Here it is, in a nutshell. (For a much longer, and far more substantiated, though of course not necessarily convincing to everyone, answer, see here.)

Philosophy began, in the Western tradition, with the pre-Socratics, and at that time, and for many centuries afterwards, its business was all-encompassing. Pretty much every meaningful question to be asked was philosophical, or had a philosophical component. Then gradually, mathematics was spun off as one of many offsprings from Mother Philosophy, followed from the 17th century on by a succession of what today we call sciences: first physics, then chemistry, biology, and eventually psychology. That did not mean any shrinking of philosophy itself, however. The discipline retained its core (metaphysics, ethics, aesthetics, logic, epistemology, and so forth) and added just as many “philosophies of” as new disciplines originated from it (e.g., philosophy of science, of language, of mind, and so forth).

In modern times, I think the business of philosophy is no longer trying to attain empirical truths about the world (we’ve got science for that), but rather to critically explore concepts and notions informed, whenever possible, by science. As Wilfrid Sellars would put it, philosophers are in the business of reconciling the manifest and the scientific images of the world. (I also think philosophy is therapy for the sane, so to speak, and a way of life.)

As a result, and this brings me to the topic of the present post, philosophical questions are unlikely to ever be answered definitively. Rather, philosophers propose a number of competing accounts aimed at increasing our understanding of such questions. Our knowledge of things will likely always underdetermine our understanding, meaning that several accounts may be equally plausible or interesting. The job of philosophers is to propose and refine these accounts, as well as discard those that have become untenable because of our progress in both science and philosophy.

1. Do we really have free will?

An incredible amount of ink has been spilled on this question over the centuries. There are religious people from the Judeo-Christian-Muslim tradition who are absolutely sure the answer is yes. And there are physicists and neuroscientists who are adamant that the answer is obviously no.

My take is that it all depends on what one means by “free will,” and moreover, that the answer doesn’t really matter. If “free” indicates some magical independence of human will from causality, then no, we don’t have it. We are part and parcel of the universal web of cause and effect, and we can’t exempt ourselves simply so that we can reconcile the alleged existence of an all-powerful, all-good, and all-knowing God with the obvious observation that bad shit happens in the world.

That said, people who are absolutely sure that we live in a deterministic universe, where the writing of these very words was a given ever since the Big Bang, are significantly overstepping their epistemic warrant. Physics has not given us, yet, an ultimate theory describing the basic building blocks of existence, and we don’t know whether the world, ato bottom, works deterministically or whether instead there is true randomness in it. Indeed, we are not even sure that so-called “strong emergence” is impossible, though at the moment I’m betting against it.

But, as I said, it doesn’t matter. We should drop the theologically loaded term “free will” to begin with, and go instead with what the ancient Greeks called prohairesis, and modern cognitive scientists call volition, the ability to make decisions. It is an indisputable fact that we have more volition than most animals, a hell of a lot more than plants, and infinitely more than rocks. It is also indisputable that we have to make decisions in order to live, that we can train ourselves to get better at them, and that it is in our own interest to do so. Anyone objecting to this is falling prey to the ancient “lazy argument,” and is just wasting your time.

2. Can we know anything at all?

Ah, well, that depends on what one means by “know,” doesn’t it? Setting aside modern debates in epistemology (the so-called Gettier problem), at a first approximation knowledge is, following Plato, justified true belief. So the debate is really about truth and justification.

There are different conceptions of truth, as I have argued at length (see here and here), so we need to be more specific. Science, and much everyday discourse, typically operate according to a correspondence theory of truth: it is true that the Moon rotates around the Earth just in case the state of affairs in the world out there corresponds with that sentence. Logic and mathematics, by contrast, work with a coherence conception of truth. To say that the Pythagorean theorem is “true” (yes, yes, within the framework of Euclidean geometry!) is to say that its conclusions are logically derived from its premises in a valid fashion.

But of course the correspondence account of truth brings up the issue of justification: how do we justify the correspondence between my utterance that the Moon goes around the Earth in terms of actual states of affairs in the world? Unlike in deductive reasoning, which is typical of both formal logic and mathematics, scientific and everyday inferences are inductive, which means we cannot be certain about them, we can only make probabilistic statements. So, in the strict sense, no, we can’t know anything (outside of logical-mathematical truths). But this isn’t worrisome so long as one is willing to accept with humility that human beings are finite and fallible. We still seem to have been able to acquire a lot of quasi-knowledge, which has been serving us well for hundreds of thousands of years.

(Notice that I completely ignored the radical skeptical challenge to the concept of knowledge, a la Pyrrhonism, or of the Cartesian doubt type. I think those challenges are both irrefutable and irrelevant, except as a good aid at checking our own hubris.)

3. Who am “I”?

This too is an age-old question, to which both scientists and philosophers have attempted to provide answers. Philosophers have come up with accounts based on the continuity of memory (what makes you who you are is your memories), on the persistence of one’s personality, or on the continued physical existence of you as a spatio-temporal being, and so on. All of these have problems, and yet all of them capture some aspects of what we think we mean when we use the word “I.” Other theories are deflationary, both in philosophy and in modern neuroscience. There really is no “you,” because your “self” is not an essence, it is, as David Hume famously put it, a bundle of perceptions.

I don’t subscribe to either the idea that there is an essence that is us (e.g., the position taken by anyone who believes we have souls), nor to the opposite notion that the self is an illusion. Personal identity is a human concept, not something to be discovered out there, either by metaphysical or scientific inquiry. It is the way we think about, and make sense of, our thoughts, sensations, and experiences. It is both true that I am, to an extent, a different person from what I was ten or twenty years ago, as well as that I am, to a point, the same (or similar enough) person. And yes, this way of thinking about personal identity is informed by a combination of the above criteria: I am who I am because I have memories of my past (in part, and anyway a disease could erase them), because I have a certain somewhat stable personality (though aspects of it have changed over time, and again a disease could alter it dramatically), and because I have been in existence as a continuous spatio-temporal “warm.”

It is true that we can come up with all sorts of clever thought experiments about unreal situations that effectively question every account proposed so far. But those thought experiments largely miss the point, because in a sense they assume that there is one true and final answer to the question of personal identity, if only we were clever enough to figure it out. That, I think, is a mistake that smells of Platonic Idealism, like asking what is the essence of the concept of chair and attempting to arrive at a definition that unifies all the objects that we label with that word, with no exceptions and no provisos.

4. What is death?

This is an easy one, as far as I’m concerned. Plenty of people seem to think that death is something mysterious, and wonder what will happen “after.” Nothing will happen, because you will have ceased to exist. Consequently, there will be no “you” (whatever that means, see above) to experience anything. There is nothing that it is like to be dead.

I arrived at this conclusion both because my philosophy is naturalistic, and because I’m a scientist, and particularly a biologist. My professor of biophysics in college, Mario Ageno, memorably defined death as a sudden increase in entropy, which disrupts the orderly functions of our our physiology and metabolism. Death is a natural phenomenon, everything passes, panta rhei. The important question, as the Stoics were keenly aware of, is what you are going to do between now and that final moment. And keep in mind that you don’t actually know when it will come. It may already be later than you think…

5. What would “global justice” look like?

This is an odd entry in the OUP Blog post, possibly a reflection of contemporary debates about justice and inequality, more than a measure of the fundamentality of the question from a philosophical perspective. Then again, Socrates did spend a lot of time inquiring into the nature of justice, so there it goes. (We get a full treatment of the subject by Socrates/Plato in the Republic.)

The OUP entry, curiously, says that “to this day, there is no universally accepted theory of justice.” But why would we expect there to be such a theory? Again, justice, like personal identity, is a human construct, not to be found “out there,” either metaphysically or scientifically. We need to have a conversation about what we want justice to mean, whether it is a worthy goal (I certainly think it is), and what are the best strategies to achieve it.

As a practicing Stoic, I quite like that philosophy’s take on the concept, which was crucial to the Stoics since justice is one of the four virtues one is supposed to practice in order to become a better human being: “The unanimity of the soul with itself, and the good discipline of the parts of the soul with respect to each other and concerning each other; the state that distributes to each person according to what is deserved; the state on account of which its possessor chooses what appears to him to be just; the state underlying a law-abiding way of life; social equality; the state of obedience to the laws.” (Incidentally, this comes from Plato’s philosophical dictionary, the Definitions.)

There is a lot going on there, and please don’t be bothered by the use of the word “soul,” which can simply be replaced with mind, if you prefer. And I discard the bit about obedience to the laws, since there can obviously be unjust laws (that part is Platonic, not Stoic). The bulk of it, however, shifts back and forth between justice as personal attitude (we are in harmony with ourselves, we make the right decisions) and a social perspective (we want each person to receive according to their desert, we wish to achieve social equality). This capture an aspect often missing from modern discussions of justice: we cannot have a just society made of unjust people. Justice is achieved through a continuous virtuous feedback loop between individuals and the society they help constitute.

That’s it folks! I have just solved five of the all-time philosophical questions! You can thank me by buying me a drink the next time you see me…

Peter Woit vs Sean Carroll: string theory, the multiverse, and Popperazism

Peter Woit vs Sean Carroll

Peter Woit (left) vs Sean Carroll (right)

The string and multiverse wars are going strong in fundamental physics! And philosophy of science is very much at the center of the storm. I am no physicist, not even a philosopher of physics, in fact (my specialty is evolutionary biology), so I will not comment on the science itself. I take it that the protagonists of this diatribe are more than competent enough to know what they are talking about. But they keep bringing in Karl Popper and his ideas on the nature of science, as well as invoke — or criticize — Richard Dawid’s concept of non-empirical theory confirmation, so I feel a bit of a modest commentary as a philosopher of science is not entirely out of order.

Let me begin with two caveats: first, there are many people involved in the controversy, including Sean Carroll, Peter Woit, Sabine Hossenfelder, George Ellis, and Joe Silk (not to mention astute commentators such as Lee Smolin and Jim Baggott). Refreshingly, almost all of them have respect for philosophy of science, unlike ignorant (of philosophy) physicists like Lawrence Krauss and Stephen Hawking. So, who knows, some of them may even read the following with some interest. Second, I actually know most of these people, obviously some better than others. I like and respect them all, even though — as we shall see — in this post I will come squarely down on one side rather than the other.

And what are these sides? For this round, I’ll focus on an exchange between Sean Carroll and Peter Woit on the specific issue of multiverse theory, though the two disagree — for the same reasons — also about the status of string theory. I have published an extended commentary on the string wars at Aeon magazine, after having participated to a conference organized by Dawid, where Peter, unfortunately, had not been invited, and which Sean, equally unfortunately, couldn’t attend.

Sean has recently written a post at Preposterous Universe entitled “Beyond falsifiability,” in which he summarizes a paper of his, currently at arxiv.org: Beyond falsifiability: normal science in a multiverse. Here is the abstract of that paper:

“Cosmological models that invoke a multiverse — a collection of unobservable regions of space where conditions are very different from the region around us — are controversial, on the grounds that unobservable phenomena shouldn’t play a crucial role in legitimate scientific theories. I argue that the way we evaluate multiverse models is precisely the same as the way we evaluate any other models, on the basis of abduction, Bayesian inference, and empirical success. There is no scientifically respectable way to do cosmology without taking into account different possibilities for what the universe might be like outside our horizon. Multiverse theories are utterly conventionally scientific, even if evaluating them can be difficult in practice.”

Not so fast, replies Peter at his blog, Not Even Wrong: “Much of the problem with the paper and blog post is that Carroll is arguing against a straw man, while ignoring the serious arguments about the problems with multiverse research. … None of those references [in the paper] contain anything like the naive argument that if we can’t observe something, it ‘simply shouldn’t matter,’ or one should not speculate about it, or it ‘shouldn’t count as science at all.’”

A good part of the discussion hinges on Sean accusing critics of both string theory and the multiverse of “Popperazism,” a neologism coined by him (as far as I can tell), which refers to the alleged misappropriation of the ideas of influential philosopher of science Karl Popper. Indeed, Sean already wrote a short piece for Edge back in 2014 in response to the question: “What scientific theory is ready for retirement?” His answer: falsificationism, the notion, proposed by Popper, that what demarcates science from non-science (and pseudoscience) is the feasibility of falsifying the tenets of a given theory or hypothesis. If a theory is in principle falsifiable, argued Popper, then it is scientific. If there is no way to subject it to the falsifiability criterion, it isn’t science.

Setting aside that falsificationism is not a scientific theory, but rather a notion in philosophy of science (after all, how would you falsify Popper’s account?), Sean admits that he hasn’t gone over the nuances of what Popper actually wrote. That’s unfortunate, because Popper was a bit more of a sophisticated philosopher than he is usually given credit for. Even though his ideas are no longer current in philosophy of science (you know, philosophy does make progress!), if one invokes him to dismiss a scientific theory (as Ellis and Silk do), or, conversely, rejects his insight in order to deflect criticism against one’s favorite theory (as Sean does), it would be good to take a look at what the men actually wrote.

Without going into too much detail (for an in-depth discussion and pertinent quotes see my Aeon article mentioned above), Popper realized that falsification is not a sharp blade capable of neatly cutting off science front non-science. He was also aware of, and discussed at length, the fact that legitimate scientific theories do include ad hoc explanations that are used by scientists as place holders until (and if) they figure out what is wrong with the theory they are working on. Nobody has ever rejected a scientific theory because all its statements were not immediately falsifiable, nor did Popper suggest such a crude practice in the first place.

To be fair to Sean, he says that what he is after is the naive version of Popper that he thinks others are using as a blunt instrument to dismiss string theory and the multiverse as outright unscientific. But, as Peter points out, evidence of such extreme “Popperazism” is hard to come by. Here, for instance, is the above mention George Ellis, in a response to a critique by Daniel Harlow, which Sean quotes approvingly:

“The process of science — exploring cosmology options, including the possible existence or not of a multiverse — is indeed what should happen. The scientific result is that there is no unique observable output predicted in multiverse proposals. This is because, as is often stated by proponents, anything that can happen does happen in most multiverses. Having reached this point, one has to step back and consider the scientific status of claims for their existence. The process of science must include this evaluation as well.”

Peter comments: “The problem with the multiverse is that it’s an empty idea, predicting nothing. It is functioning not as what we would like from science, a testable explanation, but as an untestable excuse for not being able to predict anything. In defense of empty multiverse theorizing, Carroll wants to downplay the role of any conventional testability criterion in our understanding of what is science and what isn’t.”

Does Sean do that? It appears so when he says: “The best reason for classifying the multiverse as a straightforwardly scientific theory is that we don’t have any choice. This is the case for any hypothesis that satisfies two criteria: (i) It might be true; (ii) Whether or not it is true affects how we understand what we observe.”

Those are exceedingly weak criteria indeed. As an extreme example, take the very fuzzy notion of God: it might be true, and whether it’s true or not this would affect how we understand the world. So what? Neither of those two observations — in itself — provides an iota of reason to believe in God. Or the multiverse.

Sean then moves to another target critics of string theory and the multiverse often aim at: Richard Dawid’s notion, mentioned above, of a new science based on what he calls “non-empirical confirmation.” As Sean acknowledges, that term was probably really bad PR on the part of Dawid:

“It sounds like Dawid is saying that we can confirm theories (in the sense of demonstrating that they are true) without using any empirical data, but he’s not saying that at all. Philosophers use ‘confirmation’ in a much weaker sense than that of ordinary language, to refer to any considerations that could increase our credence in a theory. Of course there are some non-empirical ways that our credence in a theory could change; we could suddenly realize that it explains more than we expected, for example. But we can’t simply declare a theory to be ‘correct’ on such grounds, nor was Dawid suggesting that we could.”

Hmm, as a philosopher, I don’t actually subscribe to this notion that we use “confirmation” in a weak sense at all. Still, Sean is right that we may, in the course of exploring the logical entailments of a given theory, discover that it has many more than we at first thought. Indeed, this is precisely what happened during the early history of string theory, and why it has attracted so much attention for so long. As for Dawid’s not suggesting that a theory should be declared correct on just such grounds, this is true. But it is also true that the whole point of Dawid’s Bayesian-informed approach is to make the argument that our belief in a theory should be updated, and even tilted toward provisional acceptance, on the basis of non-empirical entailments. This is controversial to say the least, both among philosophers and among scientists.

Sean continues: “Nobody is trying to change the rules of science; we are just trying to state them accurately. The multiverse is scientific in an utterly boring, conventional way: it makes definite statements about how things are, it has explanatory power for phenomena we do observe empirically, and our credence in it can go up or down on the basis of both observations and improvements in our theoretical understanding. Most importantly, it might be true, even if it might be difficult to ever decide with high confidence whether it is or not.”

There is a lot to unpack in those sentences. Beginning with the end, again, yes, multiverse theory may be true, but if we will never be able to decide that on the basis of empirical observation it simply shouldn’t count as a scientific theory. Nor should it be considered “probably” true, pace Dawid’s Bayesian approach. Indeed, at the moment, at least, the notion of a multiverse should be classed as scientifically-informed metaphysics. Too bad that so many scientists recoil from the “m-word,” though.

In terms of not trying to change the rules of science, I beg to differ. Maybe Sean isn’t, but Dawid definitely is. That’s a major point of his book on the subject. The question is whether such change is warranted or not. (I don’t think so.)

Moreover, there seems to me — as a naive external observer to the debate — to be nothing “boring” or “conventional” about the multiverse. It is, rather, a radical theory that would dramatically revise our whole conception of what a “universe” is in the first place!

Here Woit again makes some sharp comments: “[What] Carroll ignores is that the evaluation problem is not just ‘hard,’ but actually impossible, and if one looks into the reason for this, one finds that it’s because his term ‘the theory’ has no fixed reference. What ‘theory’ is he talking about? One sort of ‘theory’ he discusses are eternal inflation models of a multiverse in which you will have bubble collisions. Some such models predict observable effects in the CMB [cosmic background radiation]. Those are perfectly scientific and easy to evaluate, just wrong (since we see no such thing). Other such models predict no observable effect, those are untestable. ‘Hardness’ has nothing to do with it, the fact that there is some narrow range of models where tests are in principle possible but hard to do is true but irrelevant.”

Here we get pretty close to the edge of my competence, and I am going to leave it to Sean, Peter and the rest to evaluate what actual (novel) predictions multiverse theory makes, and whether and how they might be tested. But the more time passes (and this goes for string theory as well), the more the burden of proof rests on defenders of the theory, while the skeptics are increasingly justified in their impatience regarding the current dearth of such tests.

Sean concludes his post by writing that “understanding how science progresses is an interesting and difficult question, and should not be reduced to brandishing bumper-sticker mottos to attack theoretical approaches to which we are not personally sympathetic.”

That is most certainly true, though again I see little evidence of bumper-sticker brandishing. But it is curious to me that he seems to imply that his critics attack string theory and the multiverse because they are not “personally sympathetic” to those notions — not because they honestly see intellectual problems with them. This comes close to poisoning the well, a type of elementary logical fallacy that Sean is usually too careful a thinker to indulge in. Besides, what makes him so confident that he and other defenders of strings and multiverse aren’t just as much personally invested in those notions, and hence subject to more or less unconscious biases? As Caroll Tavris and Elliot Ar0nson memorably put it, “mistakes were made, but not my me.”

_____

Postscript: the term “Popperazzi” appears to have been used first by Leonard Susskind, at least since his 2006 “The Cosmic Landscape,” p. 192 (with thanks to various commenters on Twitter, especially Jim Baggott).

Also, entirely coincidentally, Sabine Hossenfelder has a (critical) piece on the multiverse at NPR.org.

On arrogance (with notes on souls and cosmic consciousness)

The NYAS panel, left to right: Emily Esfahani Smith, yours truly, Michael Ruse, host Steve Paulson, and Jay Lombard

Last week I participated to an interesting panel discussion at the New York Academy of Science, on “Seeking the why of our existence.” We were supposed to talk about meaning and purpose. I am usually somewhat weary of these sorts of panels, as the topic is often vague and open to far too much interpretation, and you never know what the other panelists’ take is going to be until you are on stage and find yourself thinking: “how do I respond to that??”

Nevertheless, I accepted, partly at the prospect of enjoying the stunning view of Manhattan from n. 7 World Trade Center, where the Academy is located, partly because my esteemed colleague Michael Ruse was also on the panel, and partly because, well, how bad could it possibly be? Joining Michael and me were Jay Lombard, MD, Clinical Director of Neuroscience at LifeSpan Medicine; creator, co-founder, and Chief Scientific Officer at Genomind; author of “The Mind of God: Neuroscience, Faith, and a Search for the Soul.” And Emily Esfahani Smith, MAPP, Writer, journalist, and author of “The Power of Meaning: Crafting a Life That Matters.” The whole thing moderated by journalist Steve Paulson, Executive Producer of Wisconsin Public Radio’s “To the Best of Our Knowledge.”

Sure enough, it was not bad at all, it actually turned out to be a pleasant evening with good questions from the audience and very able moderation by Paulson. Still, I managed to get called “arrogant” twice, by two fellow panelists (and a third time by a member of the audience), one of whom was Michael himself! (If you know Michael, genial Brit that he is, you may think it odd that he would hurl such an insult to someone else.) My Stoic training has taught me not to get offended, so I responded with humor rather than resentment. But the whole episode made me think about why I do so often receive such label. Immediately discarding the admittedly possible answer that I really am arrogant, I figured something else must be afoot.

Let’s begin with the basics, that is, with the dictionary definition of arrogant:

1. Making claims or pretensions to superior importance or rights; overbearingly assuming; insolently proud.
2. Characterized by or proceeding from arrogance, or a sense of superiority, self-importance, or entitlement.

Now let me tell you why first Jay Lombard, MD, and then Michael himself, thought it appropriate to use the epithet with me. You will be the judge of whether they were justified.

Lombard, pretty early on in the evening, said that — as a neuroscientist — he thinks it is obvious that souls exist. I did a double take, shook my head, and asked what he meant by that. He was ambivalent. On the one hand, it seems, he meant what most people mean by that term: some sort of vaguely defined, incorporeal thing that survives our bodily death and decay, and that in some way carries our “essence” to whatever “next stage” of existence. But when I pressed him, he said that the soul was “the same as” the self.

Well, for one, those two definitions are not at all compatible, unless by “self” one means an incorporeal thing that survives our bodily death and decay — and most people, especially cognitive scientists, definitely do not mean that when they use the word. Moreover, as I pointed out to Lombard, the “self” is, at best, a dynamic “bundle of sensations,” as David Hume so perceptively described it back in the 18th century. And modern cognitive science is squarely behind this notion, as opposed to some Platonic conception of the self as being an unchangeable essence of who we “really” are.

Moreover, I told my interlocutor that he was engaging in a bit of bate and switch: if by “soul” he truly meant the self, why was he using a word so metaphysically and theologically loaded. If, conversely, he meant the above mentioned immaterial essence, then I was pretty confident that there is no such thing. That, of course, is when I got the label of “arrogant.”

Arguably, I should have been more careful with my language. I should have said that there is no scientific evidence for the existence of souls (defined as above), and that, moreover, there is no particular reason to think they exist. Hence, it is perfectly reasonable to take the provisional position that they don’t, until proven wrong. To invoke Hume again, a reasonable person proportions her beliefs to the evidence. No evidence, no justification for belief. It’s as Bayesian as that. But these qualifications should have been obvious from the context of the conversation, with no need to spell them out. Lombard, instead of seeking clarifications of my position (as I had done of his) chose to interpret it in the least charitable way possible, a good rhetorical move, perhaps, but a bad philosophical one.

The discussion went off in a number of other directions, and then I got a second “that’s arrogant” accusation, near the end of the evening, this time by Michael Ruse. I do not, unfortunately, recall the precise wording of that bit of the conversation, but what I was arguing was that human mental powers — including consciousness — are of a degree the like of which is nowhere to be found in the animal world. Again, I probably should have been very careful to clarify that what I meant by that was that the quantitative differences between us and every other living organisms are such that they essentially amount to qualitative differences, not that they are, in fact, qualitative. But Michael — a philosopher! — decided to use the same rhetorical strategy adopted by Lombard, rather than actually engage in a conversation. Scoring points, apparently, is more essential than understanding.

Now, my position on this is far from radical or unsubstantiated, and is very well defended, for instance, by one of the scientists who has actually spent decades of his career studying cognition in humans, as well as its evolution: Kevin Laland, the author of Darwin’s Unfinished Synthesis: How Culture Made the Human Mind, the book we are going to tackle next in our book club series. He has tons of evidence that licenses the conclusion that human beings are incredibly different from anything else on earth, when it comes to the mind.

I know that in these times of revived interest in panpsychism it is not cool to say that humans are special, even though researchers who actually work on these issues agree that they are (in the so-quantitative-that-it-becomes-qualitative sense just described). Hell, some people even think that bacteria and plants are conscious, though of course there is not a shred of evidence that they are (invoking Mr. Hume again). On my part, I simply think that one ought to be careful about making those claims, if nothing else because vegetarians and vegans are going to be really upset. (I’m not kidding: I have vegetarian friends who are very concerned by the possibility that the carrots they eat may be sentient.)

So I fully expected a negative reaction from Lombard, but not from Michael! And yet he accused me of going “Cartesian,” as in assuming that animals are simply robots, while only humans have the divine spark. This would be comical except for the fact that Michael ought to have known better. We have frequented each other, and known about each other’s work, and in fact even collaborated on a number of projects, for literally decades. He knows I am an atheist (which means I don’t believe in divine sparks of any kind), and that I am an evolutionary biologist (which means that I don’t believe in any sort of qualitative exceptionality of Homo sapiens). And yet, I was the arrogant one because I stated the obvious, scientifically grounded, reality, while he got away waxing poetic about the entirely implausible, and certainly completely lacking in evidence, notion that rocks and atoms have degrees of consciousness!

Back to the definition of arrogance, seems to me pretty clear that I wasn’t “making claims or pretensions to superior importance or rights,” was not “overbearingly assuming,” and certainly not “insolently proud.” But I was reminding the good doctor Lombard, as well as my colleague and endowed chair professor of philosophy, that honest intellectualism is bound by reason and evidence. If there is anything that could reasonably qualify as arrogant is precisely what both Lombard and Ruse where doing: making sweeping ontological claims, i.e., claims about what is real, without a shred of empirical evidence to back them up. This, after all, was a panel discussion held at the NY Academy of Science, not of science fiction, fantasy, or wild speculation. It is a disservice to the public to lend credence — with impressive titles such as MD and PhD — to notions that are speculative at best, and incoherent or false at worst.

Do I know for a fact that atoms are not conscious, or that souls do not exist? Nope. But in both cases the burden of proof is squarely on the shoulders of those who do. It is not arrogant to proportion one’s beliefs to the evidence. On the contrary, it is the only epistemically modest thing to do.

True love, fungible love, and the Flash

Barry Allen (the Flash) kisses Iris West

Is love possible across multiple worlds? Does True Love (TM) exist, metaphysically speaking? These and other fun questions are addressed by Mike LaBossiere in an article that is as much fun to read as it is an example of how philosophy — particularly metaphysics — can seriously miss the point when it comes to crucial aspects of our lives. Let me explain by way of a story concerning one of my favorite superheroes, the Flash.

In season 2, episode 13 of the television series, entitled “Welcome to Earth-2,” Flash — the fastest man on Earth (one) — travels to a parallel Earth in order to figure out how to defeat the supervillain of the season, a guy named Zoom. It doesn’t matter why all this is happening, what matters is that Flash, known to the world as Barry Allen, meets the doppelgänger of the love of his life, Iris West. Barry-1 is perfectly aware that he is in the presence of Iris-2, who is a parallel version of the woman he loves, not the “real” thing. And yet, he simply can’t avoid having the same feelings for Iris-2 that he has for Iris-1 back on Earth Prime.

LaBossiere’s article explores the metaphysics of this situation, considering two possibilities: (i) it is rational for Barry-1 to be in love with Iris-2, on the grounds that Iris-2 is, for all effective purposes, the same woman he fell in love with on Earth-1, meaning that she looks the same, has the same interests, sense of humor, way of speaking, and so forth. Love, in this scenario, is fungible. Or: (ii) it is not rational for Barry-1 to be in love with Iris-2 for the reason that she is not his True Love, even though she looks and acts like it.

LaBossiere defends position (i), pointing out that (ii) stems from a metaphysically Kantian, and highly doubtful, view of the self. I will argue that the real answer is indeed close to LaBossiere’s, but that it makes more sense to arrive at it by way of a very different route. Indeed, this has already been done by one of my favorite philosopher-comedians: Tim Minchin. Let’s parse this out carefully.

I’m going to start from option (ii), the “Kantian” view. As LaBossiere is careful to point out, Kant never actually wrote about True Love. But he famously did reject David Hume’s view of the self as just a “bundle of perceptions,” thinking instead that our experiences happen to a unified, metaphysically “thick,” self. A metaphysical self is necessary in order to talk about True Love, the sort of love that Barry Allen can feel only for Iris West-1, and not for her doppelgänger. This is because if Kant is right, and there is such thing as a metaphysical self, then each of us has one and only one self, and anyone who merely looks or talks like us is still (metaphysically) quite distinct from us.

One way to make sense of this position is to imagine meeting for the first time your loved one’s twin. You might naturally feel attracted by her, especially if the twin has no only the looks, but also the opinions and mannerisms of your love. But, according to LaBossiere’s interpretation of Kant, you would be mistaken: regardless of superficial similarities, the twin is metaphysically, at her core, simply not your love.

This, says LaBossiere, goes well with the Dysneyesque intuition that a lot of people seem to share that there really is such a thing as True Love. The problem, as he acknowledges, is that the notion is both scientifically unfalsifiable and metaphysically suspect, and that Hume’s view of the self is actually far more convincing than Kant’s. Hume’s take both makes fewer arbitrary assumptions and is more congruent with what we actually observe via introspection. Not to mention that it goes better with much modern research in cognitive science. As Hume famously put it:

“When I enter most intimately into what I call myself I always stumble on some particular perception or other….and never can observe anything but the perception.” (Treatise, 1.4.6. para. 3)

If that is the case, let us then consider option (i): love is fungible, as they say. It makes sense to be in love with anyone who shares a substantial number of physical and mental characteristics with your original love, other things being equal.

Here LaBossiere helps himself to the idea of parallel universes, in effect arguing that what Barry Allen finds attractive in, and the reason he falls in love with, Iris West, is just the sum total of Iris’ characteristics, from her physical appearance to her interests, from her mental abilities to her moral character. If this is true, it follows that it is perfectly reasonable for Barry to be in love not just with Iris-1, but with any Iris from any of the infinite parallel Earths (so long as, I suppose, their individual life trajectories don’t actually lead them to become adult human beings that are significantly different in some crucial respect from Iris-1).

As LaBossiere summarizes the point (I changed the specific names he uses to keep with the example from The Flash):

“While this is less romantic than the idea of metaphysical True Love, it is more realistic and intuitively appealing. When one person talks about why they love another, they talk about the qualities of the person. Some dating services also make a big deal about testing people for various qualities and using them to find compatibility and love. Scientists also talk about the emotion of love as being driven by genes in search of suitable genes to combine with. Given this evidence, it seems reasonable to conclude that when Barry loves Iris, he loves her qualities. As such, if it was rational for Barry-1 to love Iris-1, then it is just as rational for Barry-1 to love Iris-35756. There is, after all, no discernible difference between the Irises.”

LaBossiere’s conclusion strikes me as fundamentally correct, but it is also an example of what Italians sarcastically refer to as the Ufficio Complicazioni Affari Semplici (Office for the Complication of Simple Affairs). I mean, sure, one can invoke the multiverse to make the point, or — far more simply — one can do like the above mentioned Tim Minchin, and simply look at the issue from the point of view of basic statistics and biological-cultural diversity among human beings.

In his “If I didn’t have you,” a song dedicated to his real life wife and long time love, Sarah, Tim says, in part:

“If I didn’t have you [insert a number a good things about Sarah]
You would think I would have somebody else
If I didn’t have you, someone else would do
[more good things about Sarah]
Your love is one in a million, you couldn’t buy it at any price
But out of the other 999,999 possible others
Someone else would be equally nice
Or maybe not nice, but say smarter than you
Or dummer but better at sports
I’m just saying, I would probably have somebody else

It is just mathematically unlikely that I would stumble
On the one woman specifically designed for me

I don’t think you are special. I mean, you are special
But you fall within a Bell curve.”

You get the gist. Minchin has simply and straightforwardly gotten rid of the “Kantian” idea of True Love, as well as endorsed LaBossiere’s point about the fungibility of real love. All without the need for any metaphysical heavy lifting (assuming that metaphysics can, in fact, do any lifting at all). A simple understanding of how life works, a basic appreciation of probability theory, and a good sense of humor will do just fine.

I’ll leave you with the full video of Minchin’s song, well worth watching: