In a recent comment, Fifthmonarchyman engaged with my accusation that his remarks on what brains can’t do is based on his ignorance of neuroscience. He responded by saying
it’s not about neuroscience it’s about ontology.
Brains don’t comprehend because they are not minds. I would think that someone so enamored with philosophy would have a handle on different categories of existence.
It is precisely as a philosopher that I want to express my complete rejection of the assumptions implicit in this remark.
The key assumption here is that there is a basic distinction between science and metaphysics. There are many ways of parsing this distinction, but here’s one that seems fairly commonplace. Science tells us the particular details about how something happens, but metaphysics tells us about the general structure of reality. If you want to know what causes hurricanes, you should ask a meteorologist — but if you want to know what is for something to <I>be</I>, you should ask a metaphysician.
There is something to this, but one is easily misled. Thus one might then come to think that there is a basic categorical distinction between mental things — those things that can reason, infer, comprehend, and decide — and physical things — those things that are described in mathematical terms and whose behavior is governed by laws of physics.
And this basic categorical division, which is arrived at in doing metaphysics, is too general and pervasive to be challenged by any scientific theory. It is too ‘deep’. Science presupposes metaphysics, therefore science cannot challenge metaphysics.
I quite agree that science presupposes metaphysics, and I am not happy with the positivists who want to liberate science from all metaphysics. (I believe a close examination of the fate of logical positivism in the hands of Quine and Sellars reveals why this was a mistake.) But I dispute the “therefore”. From the idea that science presupposes metaphysics, it does not follow that science cannot also challenge metaphysics.
For Descartes, the distinction between res cogitans (thinking things) and res extensa (extended stuff) was required in order for him to accept and reconcile an Augustinian conception of the mind and free will with a Galilean conception of matter (though Descartes rejected atomism and was severely critical of Christian atomists, such as Gassendi).
Descartes required the former in order to legitimize the authority of the Catholic Church with regard to mind and agency and thought and the latter in order to legitimize the authority of the new mathematical physics with regard to natural sciences. (To use Stephen Jay Gould’s term, Descartes was the first person to come up with NOMA — Non-Overlapping MagisteriA.)
It made sense for Descartes to urge an ontological divide between the mental and the physical because of the problems he was trying to solve.
The question is, should we continue to accept that metaphysical divide?
Now we need to get a bit more clear on the idea of “basic categories of existence”. How do we know what the basic categories are? How do we know that the basic categories are the mental and the physical? What justifies that distinction as an metaphysical distinction?
I want to say that all categories, however ‘basic’ or ‘general’, are grammatically disguised metalinguistic sortals. This means that a sentence like “Kantian Naturalist is an individual” is just the same as saying “‘Kantian Naturalist’ is a proper name”, and “desks are objects” is just the same as saying “‘desk’ is a noun”. A category is just a way of indicating the kind of semantic role that a word has in a language.
This nominalistic way of thinking about categories has profound consequences for the relation between science and metaphysics.
In the first instance, the function of linguistic roles is to detect, classify, describe, explain, and predict the goings-on in our perceptual environments. We revise our concepts as needed in order to better cope with whatever we meet with in experience. But if all categories are classification of linguistic roles, then our awareness of them is generated by reflecting on those linguistic roles in their pragmatic functions. And that means that categories cannot be immune to revision based on experience. As our science changes (as indeed it must), then so does our metaphysics.
From this briefly sketched position, it makes no sense to insist that the basic categories of 17th-century metaphysics are set in stone, fixed for all time, no matter what any subsequent science shows.
For how could that be the case? In order for basic ontological categories to be fixed for all time, unrevisable come what may, we would need to have some mode of access to those categories. We would need to have some way of piercing the veil of phenomena and beholding the noumena, or some way of getting at reality other than by poking and prodding at it with our senses and instruments.
We need, in short, to suppose that we have a cognitive power to transcend all causal transaction with particulars and simply see the fundamental categorical structure of reality.
The problem, however, is simply this: there is no evidence that we have any such power. To suppose that we have such a cognitive power is simply to invoke magic.
To reject magical thinking in all its forms is to recognize that we have no mode of access to reality except by poking and prodding it with our senses, bodies, and instruments; that our interrelated families of concepts are ways of organizing the barrage of sensory stimuli in order to cope better with whatever comes next; that even the most basic and general of categories are just metalinguistic devices for classifying words; and that there is no hard-and-fast line to be drawn between the orderly manipulation of the world (science) and the systematic conceptualization of that world (metaphysics).
In other words, a scientific metaphysics is also a completely historicized metaphysics. There is no pou sto, no Archimedean lever, no fixed point on which everything else depends — neither metaphysical nor epistemological nor semantic.