The test of such principles isn't their initial plausibility, but whether a careful examination uncovers implications that clash with our intuitions. Objections to intuitionism Intuitionism, despite its initial plausibility, has some problems. In math, principles claimed to be self-evident are precise and largely agreed on by the experts. In ethics, principles claimed to be self-evident are vague and widely disputed. Intuitionists themselves disagree widely about what is self-evident.
Moral intuitions come largely from social conditioning, and vary greatly between cultures.
So it's hard to imagine that such intuitions are a reliable guide to objective moral truths. This set has 23 problems.