Abstractions are real

I've been reading The Beginning of Infinity by David Deutsch (2011), and it's full of interesting arguments, but one point in particular stood out to me for this blog. In chapter 5, titled 'The reality of abstractions' he takes issue with the reductionist approach that argues that all explanations must be reduced to elemental levels. Here's one way he argues the point:

You know that if your computer beats you at chess, it is really the program that has beaten you, not the silicon atoms or the computer as such. The abstract program is instantiated physically as a high-level behavior of vast numbers of atoms, but the explanation of why it has beaten you cannot be expressed without also referring to the program in its own right.

Deutsch goes on to argue against Douglas Hofstadter's position that the mind "can't push stuff around", and hence against Dennett's position that the 'I' is an illusion. Deutsch sums up: "There is no inconsistency in having multiple explanations of the same phenomenon, at different levels of emergence. Regarding micro-physical explanations as more fundamental than emergent ones is arbitrary and fallacious."