Today's post is by Harriet Fagerberg at King’s College London & Humboldt-Universität zu Berlin on her recent paper “Why mental disorders are not like software bugs” (forthcoming, Philosophy of Science).
What, if anything, is the difference between mental disorders and brain disorders? Are mental disorders brain disorders? If not, are they disorders at all? According to one prominent view in the philosophy of psychiatry, mental dysfunction does not entail brain dysfunction just as software dysfunction does not entail hardware dysfunction in a classical computer. Wakefield writes:
It is true that every software malfunction has some hardware description; that is not at issue. Rather, the point is that a software malfunction need not be a physical hardware malfunction. Analogously, even if all mental states are physical states, it does not follow that a mental dysfunction is a physical dysfunction. (p. 129, Wakefield, 2006; see also Papineau, 1994)
Nevertheless, because dysfunctions count as medical disorders (per the natural dysfunction analysis of medical disorder) purely mental dysfunctions still count as real disorders. Thus, we get real mental disorders, without brain dysfunction, and without appealing to some spooky dualism about the mental.
The argument from the computer analogy is both intuitive and appealing. However, as I argue in ‘Why mental disorders are not like software bugs’, it is also unsound. The argument from the computer analogy rests on the false premise that mind-brain is analogous to software-hardware in all relevant ways. In fact, there is an important disanalogy between mind-brain and software hardware: software functions need not be hardware functions, but mental functions are brain functions.
The etiological theory of function, on which the natural dysfunction account rests, states that F is a function of X iff F is a selected effect of X.
We can now ask, are all software functions selected effects of the hardware? It seems not. We can imagine a scenario in which the hardware designers had no idea that the hardware they were designing would eventually come to run a word processer. Thus, if there is an error in the code which prohibits (say) the deletion of text, then this is compatible with the hardware doing everything it was designed to do. The hardware was just designed to run code – and it is doing this correctly.
Mental functions, on the contrary, are necessarily selected effects of the brain. The only way in which a mental function can be configured into the mind via evolution is by being causally efficacious in the natural selection of the implementing organ – i.e. the brain. There is not pre-neural ‘mindware’ designer through which purely mental norms of operation may arise. It follows that mental functions are brain functions. Accordingly, should one fail, that failure would constitute a brain dysfunction – whether or not we can determine this from physical facts alone.
In this sense, mental disorders really aren’t like software bugs.
When one is talking about mind and brain in human beings, there is something else to consider besides Darwinian selection on brain structures. There is also a very large epigenetic factor present in the form of transmitted cumulative culture. This epigenetic element overlaps with a number of the intuitive meanings of the word “mind,” and hence have to be considered.
ReplyDeleteHuman mental functions depend not just on a genetically designed program for brain development, but also on the application of the right stimuli at the right time in development. Language is the most obvious but also the simplest example of the type: If a person doesn’t learn language during a developmental readiness period, they will never be able to learn language, and in many ways won’t be fully human.
Culture is just as essential and powerful as that, but it has less stereotyped forms. Different cultural transmissions create different kinds of minds. They do so in two ways. (1) They act on the physical structure of the brain, via developmental plasticity. (2) They act on what might reasonably be called mental contents held in the brain.
The second of these two needs elaboration. The contents of a human mind are only partly generated by the local brain. A very large part of brain content consists of or works within information, behavioral rules, analytic categories, moral values and theories of mind, etc. derived from others. This content is not merely intellectual; it hooks into and deeply influences the most primal of emotions.
So now, on to mental illness. Without attempting to capture this vast subject in its entirety, let us think about a stereotyped case: A person grows up in a religious culture that emphasizes shame and guilty, and their parents do a lot of shaming and guilt-provoking; later, when this person encounters the normal challenges of life in perhaps a rather more difficult than average way, shame and guilt turn into self-hatred. At that point, the person is mentally ill. At that point their brain function is ill. But the manner of the illness is a complex combination of the physical brain and the defining mental inputs that came from the outer world.
The computer analogy isn’t any good because the epigenetic and genetic elements that compose brain function are combined in fabulously intimate and intricate ways. This is nothing like the few and stereotyped interactions between software and hardware. Software and hardware are fully discrete. Mind and brain are in no way so.