Smith vs Parfit Part 13 of 15: The Evolutionary Objection to Desire-Independent Reasons for Action
In this series of posts I am commenting on an article sent to me by a member of the studio audience. These are, in a sense, notes written in the margin as it were as I highlight passages in the article and explain my agreement or disagreement.
Currently, I am scribbling in the margins next to the quote:
According to another group of theories, reasons for acting are all provided by the facts that make certain things worth doing for their own sake, or make certain outcomes worth producing or preventing.
If we assume that humans are the current result of billions of years of evolution, there is a significant problem for any theory that suggests that there are facts of the type described above.
Evolution is going to take such facts and mold our perceptions of them in ways that promote evolutionary fitness. With respect to facts that provide their own reasons for action (or reasons to want), we are going to ask what effect evolution would have had on our ability to perceive those facts correctly.
One of the defenses for this is that these facts also identify what is good for human survival, so that a faculty to perceive and respond to these facts correctly would have proved to be an evolutionary benefit.
Where does this assumption come from?
Whenever I have asked this question of people the most common response I have been given is, Of course there is a close match between what is good and what promotes our genetic replication. Look at what it is we tend to seek and note its value with respect to promoting human survival?
But this begs the question. Of course we have desires that have tended in the past to promote (or at least not interfere too greatly) with evolutionary fitness. Evolution has tested our disposition to acquire desires with evolutionary fitness and selected those for which the disposition to acquire desires that promote evolutionary fitness over those that lacked those dispositions.
The question is not whether such a relationship exists, but what best explains that relationship.
The paragraph above seems to do a good job, as far as I can tell.
However, some theorists want to complicate the matter by adding desire-independent facts that provide reasons for action. Whereas a relationship between what we are disposed to desire and what has tended to promote human evolutionary success in the years past is easy to explain, the relationship between these desire-independent reasons for action and what promotes human evolutionary fitness is harder to account for.
In fact, I would say that it is impossible.
In the absence of a compelling reason to include them in our ontology, it is better to be rid of them and develop a theory that has no need for such entities.