A Brief Introduction to Computationalism
I just wrote the final version of an introduction to computationalism to be published in the forthcoming Oxford Handbook of Philosophy and Cognitive Science. I need to turn it in in a couple of weeks. I am posting it here in case anyone wants to take a look and give me their feedback.
Caveats:
1. In the essay I draw an initial contrast between connectionism and computational neuroscience (as well as between those two and classicism). Although philosophers often assimilate the two, many neuroscientists seem to understand those terms completely differently, that is, connectionism as having to do with biologically unrealistic psychological models, and computational neuroscience with biologically realistic models. So I think it's helpful to distinguish between the two. I would be especially interested in comments on this point.
2. Section 6 will be eliminated from the published version (mostly for reasons of space).
3. As I point out in the acknowledgments, much of this material is a revised (and in some cases, hopefully, improved) descendant of material published in previous articles of mine.
Caveats:
1. In the essay I draw an initial contrast between connectionism and computational neuroscience (as well as between those two and classicism). Although philosophers often assimilate the two, many neuroscientists seem to understand those terms completely differently, that is, connectionism as having to do with biologically unrealistic psychological models, and computational neuroscience with biologically realistic models. So I think it's helpful to distinguish between the two. I would be especially interested in comments on this point.
2. Section 6 will be eliminated from the published version (mostly for reasons of space).
3. As I point out in the acknowledgments, much of this material is a revised (and in some cases, hopefully, improved) descendant of material published in previous articles of mine.
Good to differentiate connectionist/pdp models from the more biologically inspired cognitive neuro. But you really should cite HH 1952 for that, it's the keystone:
Hodgkin, A., and Huxley, A. (1952): A quantitative description of membrane current and its application to conduction and excitation in nerve. J. Physiol. 117:500–544.
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Eric, thanks for your helpful comments. Is there any way you could expand a bit on how you'd like me to cite Hodgkin and Huxley? As constituting the beginning of biologically realistic mathematical and later computational models of neural activities?
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Yes, I would cite it as the seminal analysis of excitability in neurons based on conductance changes. It forms the basis for how pretty much every neuroscientist thinks about how neurons work at the mathematical, functional, and biophysical levels.
Something like that anyway.
We now look at HH as a special case of the more general class of conductance-based models that we all know and love:
http://www.scholarpedia.org/article/Conductance-based_models
Ermentrout has shown how PDP-type characterizations of neurons reduce to conductance based models when certain assumptions are made. Reference with later citations:
http://portal.acm.org/citation.cfm?id=188151
The integrate and fire model, which people like because it includes spike times not just rates (PDP neurons are rate-based neurons), is also an important development that can be reduced to conductance-based models in many cases. A really nice overview of this "third generation" class of models that mix the relatively lower computational load of PDP models with a bit more biological realism can be found here:
http://icwww.epfl.ch/~gerstner//BUCH.html
Ultimately of course every theorist must decide how much detail to include in a model. I just know that the type of PDP you find in the PDP volumes I and II, most neuroscientists don't consider neuroscience as much as theoretical psychology, and such models have been of very limited help in neuroscience proper compared to HH type models (as models of actual neuronal dynamics).
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Eric, thanks for these excellent points! I think you are right that adding some information along the lines you indicate would be appropriate and helpful.
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