I maintain that ethics ought to be a sub-field of evolutionary biology. My stance may lead people to surmise that I run afoul of the fact/value distinction.
- There can be natural selection for beliefs. It is a simple matter of whether the beliefs are advantageous.
- There can be selection for beliefs that are so advantageous that they cannot be eliminated even if it is discovered that they are false.
- There can be selection for beliefs that involve normative concepts. It is possible for there to be concepts that do not correspond to anything in existence.
- Thus, I can invincibly believe – in a world in which nothing is actually of value – that another individual is of value, which entails that the individual should be neither damaged nor destroyed but rather preserved from both damage and destruction.
- Once I believe that another is of value, I become committed not to damage or destroy the other, but to preserve it from damage or destruction. It is logically inconsistent to do otherwise. It can be biologically disadvantageous to do otherwise as well.
- At this point, I think we can say that I ought to neither damage nor destroy the other, but to preserve it.
For as this ought, or ought not, expresses some new relation or affirmation, ’tis necessary that it should be observed and explained; and at the same time that a reason should be given; for what seems altogether inconceivable, how this new relation can be a deduction from others, which are entirely different from it.
There is no derivation of prescriptions from descriptions among the bullet points.
There is instead an account of how an organism with obligations could come into existence.
It may be inconceivable that there could be a deduction. In contrast, it is conceivable that prescriptions could originate in an evolutionary world. It is not a deduction.
Hume could not conceive of either more than a century before Darwin.
The strictly logical point that Hume made does not entail that there can be no bridge at all from descriptions to prescriptions. It is a contemporary error to think that it does.