Lewis’s Premise (1): Everyone knows, and so believes, that there are objective moral truths.
Lewis: People blame, praise, and try influence things on the basis of the belief that certain things are really right and wrong – in some objective sense. And it really is obvious that, e.g., cruelty is wrong.
Objection 1: Many people deny that there is any objective right or wrong.
Lewis: They are always inconsistent in that they go on believing and asserting such that, e.g. some actions are unfair and that there is sometimes such a thing as the “objectively right side” in a war.
Objection 2: Our sense of morality is just a “herd instinct” that has developed (perhaps by evolution).
Lewis: Morality sometimes commands that we act in accordance with the weaker instinct (e.g. to save a drowning man). Morality sometimes requires that certain instincts be suppressed or encouraged in a way contrary to our natural impulses. So it is implausible that morality itself is an “instinct”.
[Note that Lewis is assuming that we are sometimes aware of a conflict between instinct and the Moral Law – and so that the latter is perceived as objective.]Read More