Reply to comment

 After our conversation last week, I feel like I have a better understanding of inputs and outputs, of interactions between neurons, of interactions between the environment and the nervous system. However, I am still interested in how these interactions come into being. We talked about neurons that connect the outside world to the nervous system, neurons that connect the nervous system to the outside world, and neurons that connect to other neurons. We talked about how there are orders of magnitude more neurons in one person’s nervous system than there are people on the planet and how the vast majority of those neurons connect to other neurons. I doubt that this was always the case. I wonder which of the three types of connections the original ones were. That is, can a nervous system be simplified so much that it only has one or two types of connections and still be a nervous system? Did all of the types of connections exist in the original, ancestral nervous system, or are some of them derived? Is the ability of the human nervous system to generate outputs without inputs common to all nervous systems, or is that, too, a derived trait? My question from the other week still remains: which came first, inputs or outputs?