Empricism

Deleuze considered himself an empiricist, albeit a "transcendental empiricist". 

I'm not sure I completely understand this term, but I know that it's meant to be "one level up" from the standard type of empiricism where someone declares that "all we have are sense impressions".  This goes in the right direction -- ie. away from trying to deduce what the world is really like from a bunch of logical concepts or abstract categories, towards a type of experimentalism -- but it still takes too much for granted, in particular an "I" having "a" sense impression.  It's a little like the one-liner critique of "I think therefore I am" -- Descartes should merely have said, "hey, there's some thinking going on here" and instead he's like, all your thinking are belong to us.  Philosophically, the empiricism is a pretense because you are being insufficiently empirical about the concepts you are smuggling in (the self with its possessions).  Hence you have to go up a level and get "transcendental" -- which as far as I can tell is just meant to mean something like, "before presuming subjects and objects".

A book of philosophy should be in part a very particular species of detective novel, in part a kind of science fiction. By detective novel we mean that concepts, with their zones of presence, should intervene to resolve local situations. They themselves change along with the problems. They have spheres of influence where, as we shall see, they operate in relation to 'dramas' and by means of a certain 'cruelty'. They must have a coherence among themselves, but that coherence must not come from themselves. They must receive their coherence from elsewhere.

This is the secret of empiricism. Empiricism is by no means a reaction against concepts, nor a simple appeal to lived experience. On the contrary, it undertakes the most insane creation of concepts ever seen or heard. Empiricism is a mysticism and a mathematicism of concepts, but precisely one which treats the concept as object of an encounter, as a here-and-now, or rather as an Erewhon from which emerge inexhaustibly ever new, differently distributed 'heres' and 'nows'. Only an empiricist could say: concepts are indeed things, but things in their free and wild state, beyond 'anthropological predicates'.

 As I failed neuroscientist, this is one of the most interesting and challenging aspects of Deleuze for me (and also part of what makes Whitehead so interestingly similar with his "fallacy of mis-placed concreteness").  Accept thoughts as things.  I mean, what else would they be?   Sometimes I almost think of thoughts as things that are similar to the cloud of virtual particles that are meant to surround electrons, etc ... in renormalization theory.  I just mean this as a vague analogy right now; we could quickly slip off the deep end here because its clear that once you start getting empirical about your empiricism, things get complicated and self-reflexive.  You aren't going to be able to reduce consciousness to "real things" like electrons because those electrons are actually already pretty sophisticated thoughts.  But it also doesn't mean that you can be an idealist and assume that everything is "just thoughts" -- there's plenty of "things" we haven't thought of.  

Anyhow, here's the same idea as it is presented in the Cinema 1: The Movement Image.

How is it possible to explain that movements, all of a sudden, produce an image - as in perception - or that the image produces a movement - as in voluntary action? If we invoke the brain, we have to endow it with a miraculous power. And how can movement be prevented from already being at least a virtual image, and the image from already being at least possible movement? What appeared finally to be a dead end was the confrontation of materialism and idealism, the one wishing to reconstitute the order of consciousness with pure material movements, the other the order of the universe with pure images in consciousness. It was necessary, at any cost, to overcome this duality of image and movement, of consciousness and thing. Two very different authors were to undertake this task at about the same time: Bergson and Husserl. Each had his own war cry: all consciousness is consciousness of something (Husserl), or more strongly, all consciousness is something (Bergson). 

 Empiricism and immanence and fractals are all connected.  In fact, I once maintained that all of Deleuze's concepts are meant to be these self-reflexive fractals.  Story for another day though.