A member of the studio audience asks:
Why should someone consider all desires that exist when making moral judgments? Why not just the desires of those they care about?
This question is a lot like the Hateful Craig Problem I discussed in post quite a while back. The answer here is going to start off the same, though I will take it in a slightly different direction.
See Atheist Ethicist, The Hateful Craig Problem: Why should I, who for purposes of this question hate everyone, wish to fulfill the desires of others?
This question was asked in relation to an alternative,
What if I have a humans-only morality and consider only the desires of humans?
I begin by asking, "What does the word 'should' mean in this question?" Clearly, I cannot answer the question until I know what it is that is being asked.
I hold that 'should' (and 'ought') refers to reasons for action that exist. When a person 'Why should I do X?' this can be reduced to a question of the form, 'What reasons for action are there for me to do X?'
Here, all I need to do is to point to the desires of non-humans and say, "Well, those are reasons for action that exist. When you ask what reasons for action are there for you to do X, I point to the desires of non-humans and say that there you will find reasons for action that exist for you to consider the desires of non humans."
The response at this point may be, "But I do not care about those reasons for action that exist. I choose to ignore them - to disregard them. I will not include them in my moral calculus."
However, now you are asking a different question. It is not, "What reasons for action are there for me to consider the desires of non-humans?" but "What reasons for action do I have to consider the desires of non-humans."
Desirism states that you may well have no reason to consider the desires of non-humans. The desires that you have are a very small subset of the desires that exist, and there is no reason to assume that this subset of desires includes a reason to consider the desires of non-humans.
Yet, moral claims seldom look at the reasons that a person has or doing or refraining from some action. The child rapist has a particularly strong reason to rape a child. However, the immorality of rape is not grounded on what reasons the rapist has or does not have for performing some action. It has to do with the reasons that others have for promoting or inhibiting that particular desire. It has to do with the malleable desires that people have reason to promote or to inhibit - including those desires that contribute to or inhibit the act of raping a child.
Non-human animals have reasons to act so as to promote in you desires that would contribute to the fulfillment of their desires. What non-human animals lack is the capacity to engage in a complex program of praise and blame that would help to shape those desires. Their limited system of beliefs stands in the way of them engaging in moral practices to the same degree that we do. They can make rudimentary moral judgments and impose them on others within their tribe, but they cannot participate in a complex global culture.
However, the fact that they are not capable of making the best possible plans to aid in the fulfillment of their desires does not change the fact that those desires exist and that they are reasons for action that exist.
We still have reason to promote in people generally an aversion to disregarding the desires of those who cannot fully participate in the moral culture - those who cannot plan sufficiently well to prevent being taken advantage of.
Such an aversion makes us safer. It would also inhibit actions that would be a threat to our pets and livestock and even our children. We have reason to praise those who consider the desires of agents who are incapable of fully expressing their own desires, and to condemn those who see an inability to express one's desires as a reason to disregard those desires.
"Why should I consider the desires of non-human animals?" implies "What reasons for action exist for me to consider the desires of non-human animals?" We can answer this question by pointing to the desires of non-human animals. Those are reasons for action that exist.
"What reasons for action do I have to consider the desires of non-human animals?" Answer: Possibly none. However, morality has never been concerned with what reasons for action an agent has, but with what reasons for action he should have - what reasons for action that others have reason to cause him to have. In this respect, non-human animals have many and strong reason to cause the agent to consider their interests. They simply lack the ability to act intelligently on those reasons.
Yet, the rest of us have many and strong reasons to condemn those who disregard the interests of those who cannot defend them. Many people we care about share those same qualities and, in some context, we may find ourselves unable to fully participate in the moral community either. In which case, we still have reason to have those in the moral community consider our interests. So, we have reason to praise those who consider the interests of those who cannot speak for themselves, and to condemn those who disregard such interests.
This is all that can be said on the matter. Somebody could well read this and assert that they still have no interest in considering the desires of non-humans. And they may well be right - they do not have such an interest. But the moral question is not whether they have or do not have these interests. It has to do with whether the rest of us have reason to create those interests in him through the use of social tools such as praise and condemnation.
On this question, the honest answer is that we do have reason to do so - even those of us who cannot make sophisticated plans to fulfill its desires still has reason to use social tools to create such interests in others. This remains a fact regardless of whether the agent to be praised or condemned cares about that fact.
Now, one can read all of this and still respond, "After considering these things I do not feel any interest at all in considering the desires of non-humans. Therefore, your argument fails."
However, remember, desirism states that you cannot reason somebody into virtue. Rather, you mold their desires through social practices such as praise and condemnation. The argument states that there are reasons to act so as to use social institutions to cause people generally to have certain desires and aversions. The reasons do not generate those desires and aversions. The actions that people have reason to perform are to do that.