Critics of contemporary metaphysics might have moved on from logical empiricism but the accusation that metaphysics is a waste of time has not gone away. Those like Craig Callender argue that this branch of philosophy asks irrelevant questions and answers them with unreliable intuitions. But this ignores the role of arguments in metaphysics as well as the crucial, real-world applications of its seemingly strange subject matter, writes Alexander Kaiserman.
It’s not easy to say what metaphysics is, much less what it ought to be. Most branches of philosophy are named after their subject matter – philosophy of mind, philosophy of language, and so on. The word ‘metaphysics’, by contrast, is derived from the collective title given to fourteen books by Aristotle 100 years after his death, probably as a warning from the editor that they should be tackled only after having mastered the books contained in what we now call Aristotle’s Physics. Indeed it’s not clear that metaphysics even has a subject matter as such, seeing as for anything that might be said to be its subject matter (essence, structure, etc.), denying the existence of that thing would itself be considered a metaphysical view.
Perhaps because of this, metaphysics has often been a target for those harbouring suspicions that much of philosophy is ultimately a colossal waste of time. The criticism has taken many forms throughout history. The logical empiricists argued that metaphysical views are meaningless because they cannot be empirically verified. Not many people hold this view anymore, in part because it arguably doesn’t meet its own standards for meaningfulness, but in part too because of the extraordinary progress metaphysicians have made in last 100 years or so in gradually raising the standards of clarity and explicitness in the statement of their views, helping to put to bed at least some of the traditional accusations of incoherence.
Most metaphysicians...aren't really in the business of drawing a line-of-best-fit through their intuitions.
A more common complaint nowadays is that metaphysicians are overly reliant on ‘intuitions’, pre-theoretic hunches that are (the critics allege) products of evolution, culturally variable, and ultimately not reliable guides to what the world is like. Even worse, metaphysicians, insofar as they purport to be interested in the fundamental structure of reality, are in danger of trespassing on land rightfully claimed by physicists, only with tools far less suited to the task (armchair reflection is no match for the Large Hadron Collider).
It’s probably true that metaphysics could benefit from better understanding of science and scientific practice. But the misunderstanding goes both ways. Most metaphysicians (the good ones, at any rate!) aren’t really in the business of drawing a line-of-best-fit through their intuitions. Instead what you’ll typically find if you open up a metaphysics article is arguments of one kind or another. And the best arguments – the ones that get published and discussed – are often ones with counterintuitive conclusions, which reveal some previously unnoticed tension between our pre-theoretic commitments.
Here’s a classic example to illustrate what I mean. Imagine that, using a device he has invented, Professor Farnsworth scans his own brain and manipulates your brain to put it in exactly the state his brain was in when it was scanned, and vice versa. Question: is this a body transplant or a mind transplant? Do you wake up in Farnsworth’s old body after the operation, or do you wake up in your old body just with all of Farnsworth’s old memories, beliefs, hopes, character traits and so on? Most people think it’s the former – you go wherever your psychological states go.
But now suppose that the device malfunctions and manipulates both Farnsworth’s and Fry’s brains into the state your brain was in when it was scanned. Now we have two people, both of whom are psychologically continuous with the old you. But they can’t both be you – after all, there’s two of them and only one of you! So the intuition we started with must be incorrect; you don’t always go wherever your psychological states go. What makes you the very same person as the person in your parents’ childhood photo albums, therefore, can’t simply be the fact that you are psychologically continuous with that person.
Raymond Tallis, Joanna Kavenna and Simon Blackburn debate metaphysics, morality and mayhem.
Now, you might resist this argument in various ways. Maybe there were two people in your old body all along, and the procedure merely ‘separated’ them. Maybe you aren’t one-and-the-same thing as any of your past or future selves, but you nevertheless survive by being psychologically continuous with them (and if you end up being psychologically continuous with two people at some future time, well, so much the better!). Maybe the example is under-described in some way, or contains some irrelevant detail that is warping our judgements. If any of these thoughts occurred to you, congratulations – you’re doing metaphysics!
Here’s what you can’t do, though. You can’t simply dismiss the example as farfetched, or unlikely to arise in real life. That would be to miss the point. What the example illustrates is a deep and perplexing tension in the way we unreflectively think about the world. One the one hand, it seems like we go wherever our psychological states go; on the other, it seems like a person at one time can be psychologically continuous with two people at some future time. But here’s the rub: you can’t have both. You have to choose. Arguments for one option over another might draw on a wealth of resources – logic, semantics, empirical psychology, ethics. Rarely, if ever, will they consist of a mere restatement of the intuitiveness of one’s preferred view. After all, both views seemed intuitive, at first blush – that’s what makes this such an interesting philosophical problem in the first place!
Here’s a final complaint you might have about metaphysics. Let’s grant that metaphysical views can be meaningful, distinctive, even ingenious. Let’s even grant that some of them are true. That doesn’t mean we should care about any of them, or that metaphysics contributes anything of value to human knowledge which could justify its place in the university curriculum or its receipt of limited research funding.
Who cares if the statue is identical to the lump? Who cares if there are tables, or only atoms arranged table-wise?
Consider Daniel Dennett’s example of chmess, a game of his devising which is like chess except that the king can move two squares in any direction rather than one. Imagine a well-known professor publishes a treatise on the higher-order properties of chmess. You, a more junior member of the profession, read this treatise and spot a mistake. You spy an opportunity for a publication, and with it professional advancement; so you write up your argument and send it to a journal. A third person replies to you, and a fourth to them. Before you know it, a cottage industry of increasingly sophisticated publications on the higher-order properties of chmess has developed. But none of it matters! Nobody actually plays chmess. The whole enterprise is just a pointless misdirection of time, energy, and intellect.
Dennett never intended this story as an allegory for all philosophy, just as a vivid illustration of the potential for the incentive structures in academia to produce superficially clever but ultimately worthless babble. Yet some might accuse contemporary metaphysics of a similar collective failure. Who cares if the statue is identical to the lump? Who cares if there are tables, or only atoms arranged table-wise? Well, maybe some people care (weirdos!); but why should our taxes pay for their indulgences when they could be doing something much more useful with their talents?
I take seriously this challenge. Indeed, I think metaphysicians (myself included) could probably do a lot more than they are currently doing to explain to those outside the academy why their research matters. Because it does matter, in all kinds of ways. Take the example I started with, of what makes for personal identity over time. What could be more important than knowing what sorts of changes we can survive? Sure, you might never encounter a brain-manipulation machine like Professor Farnsworth’s. But suppose a friend of yours sustains a head injury in a car accident, and the person that wakes up in their body has a completely different set of personality traits and apparent memories from the person you once knew. Wouldn’t you want to know if your friend actually survived the accident, or whether the person now in your friend’s old body is actually someone else? I would.
Metaphysicians could probably do a lot more to explain why their research matters. Because it does matter, in all kinds of ways.
There are many other examples I could give. If X non-fatally stabs Y who then dies after refusing a blood transfusion on religious grounds, does X cause Y’s death? A metaphysical question; but one which can determine whether a person goes to prison for the rest of their life. Are racial kinds natural kinds, social kinds, or non-existent? A metaphysical question, but one at the centre of debates about how to organise a political struggle. Even the most trivial-sounding metaphysical speculations can turn out to be hugely consequential – to pick just one amusing example, consider the fact that the 2000 US Presidential election turned on the question of what counts as a hole, which prompted Achilles Varzi (a leading expert on the metaphysics of holes) to ask, one imagines rhetorically, “Where were the hole experts when we needed them?”
Of course, most of us are interested in metaphysical questions for their own sake, not for their potential impacts on US Presidential elections. But the same is true in other fields too – if no-one had been interested in scientific questions for their own sake, we wouldn’t have GPS or antibiotics or quantum computing. The future payoffs of speculative research are hard to predict in advance. Figuring out which bits of metaphysics are a waste of time is like trying to figure out which half of advertising dollars are a waste of money (as the saying goes). Ultimately, human curiosity has a habit of latching on to the questions that turn out to be important in retrospect; which is probably why no-one has actually written a treatise on the higher-order properties of chmess.