I've recently been reading The Fabric of Reality by David Deutsch, which I bought because I wanted to get a primer on quantum theory. Unfortunately, so far (I'm about to start chapter 8 ) I haven't seen much by the way of quantum theory, only insomuch as he uses it to support his view of what reality consists of. In any case, this post isn't about that but rather something he mentions in the very first chapter.
He starts by explaining that scientific theories are more than predictions, but rather explanations about how the universe (or as Deutsch later asserts, the multiverse) works. He then goes on to talk about some of what he sees as the major fallacies that scientists falls into in their philosophical approach to science.
One such concept is reductionism, whereby the great physics minds of the day are currently searching for the Theory of Everything which will unite the fundamental forces of existence, catalogue all the fundamental particles and their interactions and thus give the framework for which all other concepts can be deduced.
Deutsch's opposition to reductionism is that it does not explain the current state of things because of what he calls emergent phenomena. He uses the example of a copper atom at the tip of the nose of a bronze statue of Churchill, explaining it's presence there in human terms (Churchill's popularity, the use of bronze – which contains copper – in statue building etc) rather than in terms of the copper atom itself. He even states that there should not, even in principle, be a lower-level explanation. His argument is that a Theory of Everything would explain the movement but without context.
I'll be honest, I don't see the logic. The issue hangs on whether emergent phenomena are reducible. Note that it does not depend on them being easily reducible. The resulting interdependancy of minute processes may make the maths impractical for now and the explanations of those interdependencies 7 libraries long, but such a low-level understanding would cause ripples through the body of scientific understanding as higher-level disciplines interpret their knowledge through the lens of the ToE.
Can politics be exlpained in terms of sociology? can sociology be explained in terms of biology? can biology be explained in terms of chemistry? can chemistry be explained in terms of physics? If the answer to all those is yes, than a political explanation of an event is a summary, a necessary abbreviation based on a common understanding of how politics comes to be. The physical part is implied, yet it would be the key to a true understanding.
It seems to me that Deutsch's use of the concept of emergence is a fudge. An emergent phenomena is either caused physically or it is not. If it is, it can be reduced and hence is not emergent at all. If it is not completely caused physically, then emergent isn't the right word, independent would be far more appropriate. That opens a whole can of worms about the applicable scope of the scientific method (i.e. if politics is not ultimately a result of a physical process, just what is it a result of? how would you measure and study this non-physical controller? how could you actually tell when something is independent?).
Anyway, my brain's had enough of this for one day. Next up will be how free will fits into the physically-determined world.