## NACAP 2009 – EXTENDED ABSTRACT Putnamizing the Liquid State

### BibTeX

@MISC{Kirby_nacap2009,

author = {Kevin Kirby},

title = {NACAP 2009 – EXTENDED ABSTRACT Putnamizing the Liquid State},

year = {}

}

### OpenURL

### Abstract

Echo state networks, liquid state machines, context reverberation networks – these all perform what has come to be known as “reservoir computing. ” This approach to neural computation has been getting much attention lately. I wish to show that not only is it of scientific and technological interest, but of philosophical interest as well. It is not so much that reservoir computing raises new philosophical problems, but that it casts a quarter-century old debate about how physical systems implement computations (arising from arguments made by Putnam and Searle) in a vivid new context. I set the stage by doing a quick summary of reservoir computing. I then turn to Hilary Putnam’s “Theorem ” in an appendix to his Representation and Reality, and follow it as it is recast in the subsequent work of Chalmers, Scheutz and Joslin. I then consider the dynamical systems used in reservoir computing as a kind of prototype for the dynamics referred to by these philosophers. This leads to the general notion of a dynamical system interpreting another dynamical system. In reservoir computing we see the high dimensional dynamics of physical systems (even literally buckets of water) harnessed to create context for inputs to a connectionist network. This construction proceeds in a way analogous to Putnam’s construction in the proof of his theorem. Perhaps a rock cannot simulate any finite state automaton, but, in some sense, a “reservoir ” can!