In their provocatively titled Every Thing Must Go, (2007), philosophers of science James Ladyman and Don Ross argue that metaphysics as it is practiced in much of contemporary analytic philosophy is ultimately a wrongheaded and worthless pursuit. Metaphysics takes itself to be the branch of philosophy that tackles the most fundamental questions -- 'what are the most basic constituents of reality?' 'To what extent do our concepts reflect the real structure of the world?' 'How does mind relate to matter?' and so on. Unfortunately, Ladyman and Ross argue that it will not be up to the task unless metaphysicians radically reconceive their methods. In particular, they should stop relying on common-sense intuitions, especially when these clash with our best physical theories. The authors provide numerous examples of careless metaphysicians implicitly or explicitly relying on scientifically outdated assumptions that have more to do with 'A-level chemistry' than cutting edge physics. Contemporary metaphysics, we are told, must be replaced by a thoroughly naturalistic metaphysics, which exclusively concerns itself with drawing connections between the sciences, and rejects scientifically unanswerable questions as pointless distractions.
I will not attempt anything like a full-scale review of the book (though I liked this one). I'd much rather examine some of the specific points and arguments made throughout the book. This entry will address the following excerpt, in which the authors quote a well-known introductory metaphysics textbook :
" Michael Loux and Dean Zimmerman explain the methodology of metaphysics as follows: ‘One metaphysical system is superior to another in scope in so far as it allows for the statement of satisfactory philosophical theories on more subjects—theories that preserve, in the face of puzzle and apparent contradiction, most of what we take ourselves to know’ (2003, 5). Here is a conception of metaphysics according to which its function is to reassure the metaphysician that what they already believe is true." (p. 12, emphasis mine)
The textbook states that a good metaphysical theory is one that sits sufficiently well with ('preserves') "what we take ourselves to know", that is, our basic, common-sense intuitions about the world. If a metaphysical theory has a consequence that violates such intuitions, leading us into "puzzle and apparent contradiction", this is regarded as a cost. For example, if a metaphysical theory tells us that everyday material objects like chairs and tables do not exist, there better be excellent reasons to believe said theory, to make up for the cost of violating our intuitive beliefs about such objects.
Ladyman and Ross retort that, on this conception, metaphysics serves the purpose of comforting us in the conviction that what we already believe is true. We begin with the assumptions that the material objects around us exist, that they have various properties, that they could or couldn't have existed with some of those properties, and so on, and construct theories that simply confirm those assumptions. In contrast, the sciences routinely (and sometimes dramatically) challenge our unwarranted prejudices about the world, like the belief that all facts have causes (rejected by current physics) and that 'human being' is a real category (thought to be incompatible with evolutionary theory).
Granted that metaphysicians typically try to make their theories 'fit' with their intuitive, common-sense beliefs about the world. Often, such beliefs are so intuitive because their truth is a matter of definition -- e.g. it just follows from of our concept of pain that it has to 'feel' a certain way. In other cases, common-sense beliefs are held because their truth is thought to be a necessary condition of any kind of objective inquiry. For instance, our investigation of the world wouldn't go very far without beliefs that perception, memory and basic logical reasoning are unreliable. One upshot of this is that scientific investigation, no less than its metaphysical counterpart, also relies on common-sense beliefs, but I will address that in another entry.
For now, what matters is that regardless of whether or not our intuitive common-sense beliefs about the world are warranted, the fact that metaphysicians try to devise theories that agree with them does not at all imply that metaphysical theories are just there to reassure us that what we already believe is true -- in other words, the textbook's characterization of metaphysics in no way implies Ladyman and Ross' characterization of it. What it does imply is that metaphysical theories aim for coherence, in particular, coherence with background beliefs. For example, if I believe that my wife is a human being, I will not try to explain her behavior in ways that would entail (or make very probable) her non-humanity. If she comes home later than usual on a Friday night, I will not explain this with the hypothesis that she was attending a party strictly reserved for intergalactic vampires, but rather with the hypothesis that she is at the pub with colleagues. It would be senseless here to accuse of me of trying to comfort myself in my belief that she is human.
Interestingly, much of ethics works like this as well. Ethicists will usually reject ethical theories that entail clearly false moral claims, e.g. the claim that torturing people for fun is morally permissible. But such ethicists aren't generally aren't denounced for trying to convince themselves that what they already believe is true.
Hence, it seems much more reasonable to say that on the textbook account, metaphysics serves to provide theories which cohere well with (many of) our intuitive common-sense beliefs about the world, not to reassure us that such beliefs are true. Again, this is true regardless of whether or not our intuitive common-sense beliefs are warranted (I will discuss that in another entry).
Defenders of Ladyman and Ross might respond that I am taking them too literally, and that the above quote is more of a tongue-in-cheek quip than a serious criticism of analytic metaphysics. After all, they do not really elaborate their point on metaphysics as comforting fiction, though they make the interesting claim that metaphysics' reluctance to violate intuition draws it closer to "story-writing" than to science (p.13). They spend much more time arguing that the intuitive common-sense beliefs that metaphysics tries to preserve are unwarranted.
That may well be true. But in any case, it seems useful to highlight the difference between the purpose of cohering well with our common-sense beliefs and that of reassuring us that such beliefs are true (many apologies to those for whom this distinction is obvious). At the very least, doing so defends metaphysical endeavors from a natural worry of the kind sometimes expressed by interested bystanders. Moreover, this is a good opportunity to underwrite the crucial importance of coherence to metaphysics, which, arguably, is fundamentally about the construction of a coherent world view.
Ladyman, J. and Ross, D. (2010). Every Thing must go. Oxford: Oxford Univ. Press.