Relativism is the basic idea that the truth of a matter is relative to one's perspective or circumstances.
Some things are relative. For example, a proper choice of clothing is relative to weather conditions, cultural expectations of decency, and mom's prerogative. The truth of the matter depends on these factors.
Some things, however, should not be left to perspective or circumstances. When one confuses those things that are relative with those that are absolute, one becomes subject to what I call "the tyranny of relativism." Reality does not smile kindly upon these unfortunates.
The tyranny of relativism is the bane of the two-year-old child. Everything, for her, is relative to her two-year-old, personal whim.
This reality came home to me on a recent baking adventure. Relativism guides her every decision.
Child: "I want a make a cake."
Mother: "Yes, that's what we're doing. Now we need two eggs."
Child: "No, five eggs."
Mother: "Well, just two eggs in the bowl."
Child: "I want five eggs in the 'firgerator. NOT IN A BOWL!"
Mother: "But if the eggs are in the refrigerator, they're not in the cake."
Child: "Yes, in the cake! In the 'firgerator!"
You get the idea.
The art of baking a cake is not a good time to exercise relativistic tendencies. Your cake will end up looking like (and tasting like) a pile of sawdust.
Truth, on the other hand, is beautiful. And tasty.