Why one sign is never enough dān zhēng · 为什么不能只看一个征象

A red tongue, a wiry pulse or a dislike of cold can each point in several directions. In the classical method they are weighed together, and the pattern is chosen from the combination.

This is also why "I read that a red tongue means X" is a poor way to use any TCM material — including this one. The tradition itself insists on the combination; that insistence is one of its more defensible features.