Sunday, 22 May 2016

The brain may not be a digital computer, but it sure ain't "empty"

The following article ("The empty brain" by Robert Epstein) came up in my circle of Cognitive Science friends from university on Facebook. Normally I am sympathetic to viewpoints that try to show that the brain is not a digital computer, or doesn't have a von Neumann architecture. All of these ideas are quite outdated and we probably don't have to be beating the dead horse anymore at this point. Although the article started off that way, it quickly took a turn into some very strange territory, a quite reductionistic take on what the brain is "doing". The author became apparently hell-bent on saying that nothing ever happens in the brain at all, that the only intelligent behaviour is vis-a-vis interactions with the world. The "How and where, after all, is the memory stored in the cell?" is a shocking question and dead giveaway. For starters, there is such a thing called synaptic plasticity, dendritic remodelling, and ion channel and receptor expression/recycling, all of which serve to change the neuron's input/output function as a function of experience. How can these things be so blatantly ignored when discussing the question of memory formation in the brain?

Regarding the whole "there are no algorithms, encoders, decoders, ..." bit (paraphrasing), this is also eyebrow-raising. When light enters the eye and hits the retina, the pattern and intensity of light gets converted into a series of action potentials. Why would you not call that an analog-digital converter? Also, most neurons exhibit idiosyncrasies in how they respond to different types of synaptic input. Some neurons suppress low frequency inputs, only responding to high frequency ones, or vice versa. These are, quite literally, high-pass and low-pass filters, respectively. All components of information processing systems. And we're not even getting into what we know so far regarding neural circuits, all of which strongly indicate that information processing is taking place, yes, even representation, storage, retrieval, etc.

Insofar as some patterns of electrical activity are manifested in response to particular configurations of sensory input, we are allowed, or even obligated, to say that information is being processed and transformed, so that certain patterns of (sensory) inputs can then lead to patterns of (motor) output that facilitate survival of the organism in an uncertain environment. It's kind of the point of having a central nervous system in the first place. Or is the author assuming that the brain does absolutely, literally nothing? Maybe he takes a page out of Aristotle's book and believes it's a giant radiator. This is the only way he can get away with his audacious and, frankly, ignorant statements. By "ignorant" I simply mean that his arguments would not be formulatable had he read the most rudimentary "Neuro 101 for dummies" type textbook from the past 25 years.

And this isn't even getting into deeper philosophical questions of different kinds of information processing and the nature of representation, or anything like that.

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