Reader Comments

It's all just AI

 The most common objection to the book that I hear is that modeling at the computational level invalidates any claim to biological plausibility.  Some of this is just the standard knee-jerk dismissal mechanism, but some is clearly not.

David Ritchie, who is generally sympathetic to both the book and to embodied cognitive science writes:

I also see a second theme, an attempt to test the biological model by developing partial models of language processes that can run on current generation digital computers , and more to the present point , incorporate into your account models that have already been developed, in particular the models developed by Bailey and Narayanan, each of which gets a full chapter.  The problem that this poses for me, and I suspect for many of your readers, is that these models in effect smuggle back in exactly the kind of assumptions about language processing that your biological explanation is attempting to overcome.  Thus these chapters seem, to me, to contradict the central features of your biology-based analysis.

He then quotes my cautionary notes from page 141:  "For both practical and pedagogical reasons, our computational level models are based on formalisms and techniques that are well established in computer and cognitive sciences.  There are also dangers in using conventional formalisms and methods.  None of the traditional techniques were developed for linking brain activity to behavior and they all are inadequate if used only in the conventional way.  In addition, the standard notation might be taken as the whole theory, ignoring the underlying bridge to the brain."

And goes on to conclude:

I actually think the standard notation doesn't merely ignore, but contradicts the underlying neural processes.   

Science necessarily involves levels of analysis

 I didn't make this point sufficiently clear in the book, but the following story seems to help. First consider the chemical formula:

2 SO2 + 2 H2O + O2 -> 2 H2SO4

In the gas phase sulfur dioxide is oxidized by reaction with the hydroxyl radical via a intermolecular reaction:

SO2 + OH  ->  HOSO2

which is followed by:

HOSO2 + O2  ->  HO2 + SO3

In the presence of water sulfur trioxide (SO3) is converted rapidly to sulfuric acid:

SO3(g) + H2O(l)   ->   H2SO4(l)

where (g) means gas phase and (l) denotes liquid.

And, of course, the story becomes too complex to write down if we look at the detailed physics involved.

 Science is always done at different levels of abstraction. What makes it science is that the technical treatments at each level should be consistent. This is what we are trying to do in the NTL project and what I try to describe in the book. The computational level models and formalisms (including grammars) should be both explanatory of the phenomena and consistent with all relevant constraints and findings. Some people feel that it is premature to attempt this unification, but the eventual answer will necessarily take the from of consistent theories.

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