We can now account for behavior at a deeper level than we could a week ago. We can describe the physical nature of the action potential, its speed and direction. We can see how inputs are taken in and hypothesize about how outputs are sent out. It is worth spending a week understanding these components of behavior, because we can now refer to the generation and journey of the action potential in our explanations with confidence that we are understanding each other. However, it is dangerous to assume that we have reached the most basic level of explanation for behavior. The questions brushed aside in class for lack of time, or answered with the classic explanation that we just have to accept that this-or-that exists and functions in such-a-way, are valid questions indicative of an underlying body of revelation even more important than solving the mystery of the action potential. We must remember that scientists spend lifetimes on this more intricate problem and never fully understand it. It is understandable that we need to move on due to the time limits of this course, but we must first acknowledge that something is still missing from our explanation. Like an elementary school student who is told that photosynthesis happens but is not entrusted with the explanation for such magic, we are left with a greatly simplified, basic body of knowledge. Our danger is that we should build on such knowledge without delving further into it, or use it as an excuse rather than an explanation.

Legitimate general concern. Were there specific questions "brushed aside"? If so, I apologize, and its worth taking the time to at least see what the general class of such questions is so we know what foundations might be shakey. There are indeed questions about boxes inside the neuron (how permeability changes, how pumps work, and so forth) that lots of people are productively spending lots of time on. Are those what are concerning you? If so, I agree we didn't have time to go into them in depth, and that is a deliberate (though not dismissive) choice reflecting a belief that we actually know enough about them at the moment to take a fair crack at problems at a higher level of organization. At the same time, it is certainly worth looking at how stable one expects that foundation to be. PG