If you take two words like 'tame' and 'domesticated', you're forced to think of the divergence in meaning, not the similarity. You say to yourself, in getting it clear, "A dog is a tame wolf, a cat is a domesticated tiger." A cat never really tames, while tameness is the essence of a dog's soul. You tame the wolf into a dog, but the tiger domesticates itself into a cat. In this way there's more real oppositeness between things that are like than between things that are different. The kind of oppositeness, I mean, that there is between words when you discard one in favour of another.