x understands why p iff
1: there is some q such that x stands in some relation R to the proposition that p because q and
2: in the light if standing in R to p because q, p turns out to be integrated in x's first person perspective.
For there to be a fundamental distinction between explanation and understanding then there have to be propositions which fit this schema but which cannot be explained. Why might this be so? Metaphysically, it might be that there are some truths about worldly objects which cannot be explained but only understood. Or, epistemologically, there may be some truths about worldly objects explanations of which are not in principle accessible to us but which can be understood. The idea was then that either of these possibilities required the truth of strong dualism, or the falsity of weakly reductionist naturalism such as supervenience physicalism.
Recall the condition:
1: there is some q such that x stands in some relation R to the proposition that p because q...
Why might the proposition ‘p because q’ lie outside the remit of scientific explanation? There could be something special about q or something about the ‘because’. But weak naturalism is already a commitment inconsistent with this. It holds that for every true proposition about worldly objects, q, the is a proposition q* such that
1 q* is a true proposition about the subject matter of the natural sciences and
2 either q=q* or q because q*.
So for every relation ‘p because q’ which is non-natural, there is 1) some lower level description of both elements in naturalistic terms which recapitulates the same ... because ... form and 2) the non-naturalist connection is true because of the lower level naturalistic claim. Hence weak naturalism is a commitment to the explanatory reach of naturalistic resources. For example, the supervenience base of intentional or reason 'explanations’ (I scare quote so as not to assume that these are explanations by contrast with something sui generis tied to understanding) itself explains those ‘explanations’. So the only way to block this would be to deny even a weak form of naturalism.
If this is vaguely right about the dialectic of the talk then it seems to beg the question about the nature of the potential relation of explanation and understanding by seeing it from the perspective of explanation (this is why I doubt that I followed it). Suppose we (rashly) assumed that Davidson’s anomalous monism were correct then the rational pattern of mental events picked out in accord with the constitutive ideal of rationality would supervene on a myriad of different nomologically structured physical patterns. So each token transition picked out at the mental level could be explained by the supervenience base. But that is neither here nor there for the view of understanding that is part of Davidson’s picture. It is not that particular transitions cannot be explained via the subvenient facts but that the pattern of relevant comparisons at the mental level goes missing at physical level.
This is not to deny the problems of either Davidson’s picture of mind or, relatedly, the shapelessness argument attached to the defence of moral realism against forms of reductionism but addressing them seems to go beyond this argument.
Now, however the pub calls with my good chum Floris so I will pass over the final session (on the particular case of linguistics).
