In accord with my original aim for the blog (of making my own efforts at writing transparent to my masters students), here are some very preliminary thoughts for a paper on explanation within psychiatry which I will develop over the next few days.
On the project of explaining delusions.
There are two aims in the project of explaining delusions.
One is to explain why delusional thinking comes about. An answer to that might be to postulate an extended mental structure or mechanisms whose output is the kind of thinking in question. Recent approaches within the philosophy of psychiatry can be fitted to this. Instances of both bottom up (such as those based on Maher) and top down (such as Campbell and Elian’s invocation of framework propositions) and dual factor theories can be seen as attempts to explain delusions according to this strategy. Ground level experiences or distortions of reasoning or combinations of both explain why agents form delusions.
At the same time, the explanans is of a particular sort: a particular sort of mental occurrence (state or expression) whose identity would be expected to be fixed by its content. It is the delusion it is in virtue of its content. (Pitched at the level of individual cases or general cases, or of content versus form (in one sense of ‘content’), it is the content that fixes things.)
But this idea comes under pressure in at least some delusional cases from the the difficulty of fixing those contents.
Now recent discussion of the application of an interventionlist model of causation might look to ease this. Campbell urges that whilst rational connectedness may be a deep seated model of mental causation (as communication of impulse is a model of mechanical/physical causation) it need not hold. (We should reject all such synthetic a priori claims when it comes to causation). So there is no genuine problem in developing a causal explanation of delusion even where the factors fail to ‘rationalise’ it. (A victory of explanation over understanding.) (Campbell himself is critical of the two factor model and has outlined a top down model based on deviant framework propositions.)
But this line of response fails to address the prior issue of the mental status of the state to be explained...