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3.3: Inference to the Best Moral Explanation

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  • Earlier we saw that scientists (and philosophers) sometimes use a pattern of reasoning known as inference to the best explanation to explain non-moral phenomena, e.g., the existence of minds. Ethicists use this form of reasoning also, although what is usually being explained is some clear moral intuition, or a moral judgment that nearly everyone agrees on (and seemingly for good reason). Again, the pattern is something like this:

    • A moral judgment – J – seems true, and what makes it true requires explanation.
    • Moral explanation or hypothesis T best explains the truth of J (i.e., T is a better explanation than other candidate explanations in that it makes sense of more of the data/observations/similar moral intuitions, allows us to make other moral judgments (thus enabling a kind of prediction, perhaps), is simpler, fits with pre-existing knowledge, etc.)
    • Therefore, probably T, and what’s entailed by T, are true.

    Singer seems to use this pattern of reasoning, starting with the widely accepted moral judgments that racism and sexism (and other prejudices) are wrong. He gives an analysis of what racism and sexism are – they are not easy to define – and gives an explanation for why they are wrong, arguing that this explanation is a better explanation than some rival explanations. He then argues that this explanation, which appeals to the principle of equality of consideration of interests, has positive implications for animals. Since many animals have interests, the prejudice that results in their interests being ignored is speciesism.

    Regan argues similarly, starting with the informed intuition that the men in the Tuskegee Syphilis Study were treated wrongly (p. 44; elsewhere he uses historical cases of harmful medical experiments on retarded children1). He argues that the best explanation why they way these men (and children) were treated was wrong has positive implications for animals. He argues that these men had moral rights to life, bodily integrity, and respectful treatment. He develops the “subject of a life” sufficient condition for having basic moral rights to life, to bodily integrity and respectful treatment, shows that this criterion for moral rights applies to many animals as well, and that they thereby have moral rights as well.

    In both cases, the pattern is to start with what we are confident with, think about the best reasons to support that confident judgment, and see that that these reasons have implications for areas that we perhaps have not thought about as carefully. We then see that that we have to revise our previous judgments about that new kind of case or, if we are to be consistent, revise our initial judgments (e.g., about the human cases), or argue that nothing follows from one kind of case to another because they are relevantly dissimilar. Singer, Regan and Rowlands, as well as the others, are clear on the logical options.

    1 “Empty Cages: Animal Rights & Vivisection,” essay at