There are no metaphysical questions

A friendly and hopefully constructive critique to my metaphysician friends

The Ship of Theseus, or it it?

From time to time I write an essay poking a bit of philosophical fun at metaphysics, despite the fact that some of my best friends are metaphysicians (sometimes they refer to themselves as metaphysicists, which is an interesting clue to what’s going on in that field…). This is one such essay, aimed specifically at proposing that–when we look carefully–there is no such thing as a metaphysical question. All questions in metaphysics properly belong, in my opinion, to one of the following three disciplines (or combinations thereof): science (especially physics and biology), logic, or semantics.

First, a bit of background. The term “metaphysics” originates from the Greek Ta meta ta physika, which literally means “the things after the physical things.” Although the term was not used by Aristotle, it was coined by a later editor of his works, traditionally identified as Andronicus of Rhodes, who flourished in the first century BCE.

The editor organized Aristotle’s treatises and titled the fourteen books that dealt with abstract philosophical subjects as Ta meta ta physika. This title was a practical one, indicating that these books came after the books on nature, which are collectively known as Aristotle’s Physics. The placement was likely intended as a suggestion for a philosophical curriculum, warning students that they should master the Physics (the study of the natural, changing world) before attempting the more advanced, abstract concepts in the Metaphysics.

For the subject matter that we now call metaphysics, Aristotle used other terms, particularly “First Philosophy,” described as the “science that studies ‘being as such’” and the first causes of things—essentially, the study of things that do not change. By contrast, ​Aristotle’s Second Philosophy is what is now generally referred to as natural science.

So, in a sense, my contention is that Aristotle made a mistake in drawing that distinction: there is no qualitative difference between the study of things that don’t change and the study of things that change, and both of them are the province of science (or, as I’ll explain later, of either logic or semantics). I am not the only philosopher to think so, by the way. James Ladyman, Don Ross, and others have for years insisted that the only kind of metaphysics that makes sense is one deeply rooted in science, which they accordingly simply refer to as scientific metaphysics.

My specific suggestion is that any metaphysical question is, in reality, either a scientific question (i.e., about “matters of fact,” as David Hume would put it), or an issue of logic (i.e., concerning Hume’s “relations of ideas”), or rooted in our use of language. But there is no such thing as a metaphysical question distinct and “beyond” these three possibilities. Let’s look at a first example to get more clear on what I’m proposing.

The Ship of Theseus is a classic metaphysical paradox that questions the nature of identity and authenticity over time, particularly for objects whose components are gradually replaced. The paradox apparently originates with the ancient Greek historian and philosopher Plutarch. It comes in two scenarios:

Scenario 1: The Renewed Ship (Ship A)

The Athenians preserved the ship that the mythical hero Theseus sailed on. Over time, as its wooden planks decayed, they were gradually replaced with new, sound timbers. Eventually, every single original part of the ship was replaced. The question is: does the newly restored vessel (Ship A) remain the “Ship of Theseus,” since it has spatiotemporal continuity (it was always in the harbor) but no original material?

Scenario 2: The Reassembled Ship (Ship B)

The political philosopher Thomas Hobbes later added a “wrinkle” to the paradox in the 17th century. What if someone collected all the discarded original planks and used them to reassemble a second ship (Ship B)? The final question then is: which of the two vessels, if either, is the real Ship of Theseus?

The problem has generated endless discussions, which have produced countless papers on the notion of identity over time, the idea of functionalism and continuity of form, the pertinence of essentialism and material composition, as well as the intrinsic vagueness of certain concepts.

But the answer to the problem, in my opinion, is: it depends. On what? On your definition of identity, which is a human mental construct, not something objectively “out there” (that is, mind-independent). There is no fact of the matter about the Ship of Theseus beyond the stipulated descriptions of what is going on. If you think of identity in a certain way, then there are two ships of Theseus; if you think of identity in another way, then only one of the ships is the real one. And most importantly: it doesn’t matter much. All you are doing by puzzling over the “paradox” is to try to elucidate human intuitions about the concept of identity, but you are most certainly not discovering universal metaphysical truths.

Here is a second example, also rooted in issues of identity, and one that I particularly like just because I’m an unabashed treekie: “Kirk in the transporter.”

The issue revolves around the Star Trek device known as the transporter, which works by scanning and analyzing a person (say, Captain Kirk), disintegrating the original person’s body, transmitting the information pattern describing said body to a destination, and recreating an exact duplicate of the person at the new location using new matter.

The alleged metaphysical question is this: is the person who steps out of the transporter at the destination the same person who stepped onto the pad, or merely a perfect copy? The philosophical implications of the Kirk problem are said to be momentous, with David Chalmers arguing that it is one of the reasons we should adopt dualism about the mind-body problem and moreover, as soon as the technology is available, step right into a device that will upload our consciousness to a computer (since such device poses the same conceptual problem as the transporter).

Again, countless solutions have been debated, apart from Chalmers’s dualism, with people bringing in the psychological continuity theory of personal identity, the physical continuity theory, and so on.

What’s the answer? The same as that for the Ship of Theseus. It depends on your conception of personal identity, which is not a mind-independent metaphysical object. Whether you think that Kirk dies every time he steps into the transporter (as I do) or you buy into the basic premise of the technology as presented in the show is a matter of how you use language. Note that the pertinent empirical facts as I described them above are not in question, just like they are not in the case of the Ship of Theseus. It is people’s more or less arbitrary interpretation of said facts that varies.

Beam me up or kill me now, Scotty? Image from media.npr.org.

Let’s up the ante a bit. Here are nine more metaphysical questions, each with my short answer and the field of inquiry to which it properly belongs. Of course, my answers are tentative and open to revision should new evidence come to light. But that’s the point: without evidence, there is no knowledge.

1. What is the nature of reality? Seems to me this is a question for science, by far the best approach we’ve devised so far to understand how the world works. Anything allegedly “beyond” science is idle speculation, and the current answer is: fields underlying what we call “particles.”

2. Do we have free will? Here the two pertinent fields are semantics (what do we mean by “free” will?) and science. And the scientific answer increasingly appears to be: no, we don’t.

3. What is the mind-body problem? I find myself in disagreement with a lot of philosophers of mind when I regard this as a scientific question. If so, the likely answer is that there is no such thing as the mind-body problem, since we live in a universe made of matter and energy, so that there is no “metaphysical” distinction between mind and body. Notice that such a universe is not the only conceivable one, but who cares? We want to know how our universe works, not how fantasy universes do.

4. Does God exist? What is at play here is semantics (what do people mean by “God”?) and, again, science. Historically, pretty much the only decent argument in favor of the existence of gods, deployed, for instance, by both Plato and the Stoics, was what we today call the argument from design. Ever since Darwin, that argument has been untenable, so the best provisional answer to the question is no.

5. What is personal identity? We have already considered two specific problems–the Ship of Theseus and Kirk’s transporter–that hinge on this. Once more we are dealing with semantics, because we need to agree on what “personal identity” means and, at best, logic, in terms of the logical implications of any particular definition of personal identity. It’s not an empirical question (so, no science needed), and there is no independent metaphysical dimension to it.

6. What is the nature of time? In this case we are faced, it seems to me, with an uncontroversially scientific question, and the best answer available so far comes from general relativity.

7. Do abstract objects exist? No empirical evidence is, obviously, germane here. So it all depends on semantics (what do we mean by “exist”?) and logic. In some sense, abstract objects (like concepts, or mathematical entities such as numbers) clearly exist. But the answer doesn’t hinge on any profound metaphysical insight, only on what we decide to count as what does and does not exist.

8. What is causation? There are different philosophical accounts of causation, and they serve different purposes depending on the specific context. For instance, some theories define causation in terms of counterfactual dependence: an event c causes an event e if and only if, if c had not occurred, then e would not have occurred. Did lack of water cause my plant to die? Yes, because had I watered it, it would probably still be alive. By contrast, according to process/mechanistic theories causation involves a physical process or mechanism that connects the cause and the effect, transferring a conserved quantity, or a “mark.” The causal link is a local, physical phenomenon, like energy or momentum. This is especially useful in physics, for evident reasons. But it’s not like one of these accounts is “true” and the others false. They represent different ways to think about the interdependence of phenomena in the world.

9. Why is there something rather than nothing? We’ll probably never know the answer to this one, simply because we have no empirical access to what existed before there was “something,” i.e., before the Big Bang. But if an answer is ever forthcoming, surely it will be from the domain of either fundamental physics or cosmology.

So, what becomes of metaphysics as a distinct philosophical discipline if this analysis is correct? Nothing particularly dramatic, I would argue. Metaphysicians can continue to do excellent work–many already do–but with the understanding that they are actually engaged in conceptual analysis (semantics), the exploration of logical implications (logic), or empirically informed theorizing about the fundamental structure of reality (science, especially when following Ladyman and Ross’s scientific metaphysics approach).

The real issue is one of intellectual honesty and clarity: by pretending that there exists a special domain of inquiry “beyond” or somehow independent of these three well-established fields, metaphysics risks generating pseudo-problems–questions that appear profound but dissolve once we realize they hinge on semantic choices or await empirical investigation. My friendly critique, then, is not that metaphysicians should stop asking their questions, but rather that they should recognize what kind of questions they’re actually asking. The ancient editor who placed those fourteen books “after the Physics” may have inadvertently created the impression of a separate realm of inquiry, when in fact the truly interesting work lies firmly within the natural world and our attempts to understand it through science, reason, and careful attention to how we use our words.