In philosophy, de gustibus is used to distinguish
discussions of subjective versus objective truth. If you tried to prove
that vanilla was the best flavor of ice cream, the only thing I could
really say would be, "De gustibus non est disputandum," (aside from that
fact that I would agree).
It's perfectly true that I like vanilla best, and that as far as I'm
concerned it's the best flavor. But in regards to subjective issues,
issues "of
taste", truth is truth for me. What is absolutely true of
me is totally inapplicable to you. This as compared to "objective truth",
(for those who believe in it), which is
independent of the
perceiver.