2010-07-14
Can we make room for developmental constraints?
Reply to Haines Brown
Haines, I do not understand everything you say, but I agree with most of what I understand and I do sense a convergence of ideas here, although I am not sure how exactly,

You write:

I had assumed, and you didn't object, that living organisms are hard-wired to perpetuate themselves and so have a build-in Telos. This seems to imply living organisms have a physical measure of success. If they do not eat, they die, and so eating is a better course of action.


I agree (more or less - I do not think that from 'if they do not eat, they die' it follows that eating is always the better course of action).

 
If you happen to agree, it does have the interesting implication that all the talk about the need for consciousness to offer a measure of sucess is not accurate.


*All* the talk about the need for consciousness to offer a measure of success? I am afraid I get caught now, but I don't know about any such talk.

Concerning your example of an organism that tarried to evade a predator and missed the opportunity to seize upon a food source you write:

So we have a need, which, although having a hard wired basis, is not a physical property but a pre-condition of life, standing in relation with a possibility in the environment, not actual empirical properties but a possible effect of properties.


I have the impression that you are confusing different notions of needs and different kinds of explanation.  As I explained in my "The Functional Perspective of Organismal Biology" (2005), I think (as do many biologists)  that in order to understand living systems one needs a combination of explanations of four kinds to explain organisms and their behavior: mechanistic explanations, design explanations (usually called functional explanations), developmental explanations and evolutionary explanations.

As you indicate, in your example the mechanistic explanation might be that he organism evaluated its actions according to its present needs and concluded that it was best to give priority to avoiding predators over seizing a possible source of food. This means that the organism must have a hard wired representation of what is worth getting, as well as a mechanism to compute the score of different actions on these values and, perhaps a mechanism to change the computation based on the results of the chosen action. This explanation talks about needs as that what the organism values. Let's call needs in this sense subjective. These needs are hard-wired into the organism.

There is another sense of 'need', namely: that what the organism actually needs to stay alive. Let's call this the objective needs. Objective needs are hard (if the organism does not satisfies them it dies) but unlike subjective needs not hard-wired. As you aptly say, objective needs are pre-conditions for life. But these are not the kind of needs that figure in the mechanistic explanation.

I agree that the mechanistic explanation above does not suffice to understand the behavior, In my view, the very nature of a mechanism as a system *organized* for the production of a certain behavior means that a mechanistic explanation never suffices to understand a mechanism. In order to understand the behavior of an organism the mechanistic explanation must be supplemented with a design explanation, a developmental explanation and an evolutionary explanation.

I don't see that the mechanistic explanation above presents the behavior of the organism as the passive result of the environment acting upon the organism. In my view, a choice mechanism is a paradigmatic example of an active response to what happens in the environment,

The design explanation will start with the 'observation' that it is an objective need that the subjective needs are such that they help the organism to satisfy its objective needs and will continue by showing that the subjective needs satisfy this constraint but it cannot explain how that state (the state of the subjective needs being such that they help the organism to meet its objective needs) came about. For that reason it is not a causal explanation.

Developmental and evolutionary explanations explain how the mechanism came to be the way it is and hence how come that the subjective needs are tailored to the objective needs,

I am afraid that I get caught a second time, for I have no idea what you mean when you talk about "the old fashioned functionalism based on causality". 

I'm left with the feeling that [...] a different notion of explanation is involved that does not look to necessity, but to possibility


In my view, design explanations are concerned with what mechanisms can be alive, so in that sense they are concerned with possibility rather than necessity. However, because it is necessary that the actual form is one of limited number of possible forms, I am of opinion that design explanation show that the phenomenon to be explained is somehow necessary. (Newton's laws do not show that the moon necessarily circles around the earth, only that this motion is one of the possible forms in which a two-body system can exist!)