Similarly, white and black are antonyms because they are alike in that they -denote extremes in the range of achromatic colors, but different in that they are at the opposite extremities of the color range, while grey is both a different color from white and black and not at an extreme point on the scale. And while happy contrasts with sad and angry and surprised and afraid, it seems to have the most in common with sad, since (among other reasons) happy and Sad reflect states with reversed facial expressions (smile/frown) and postures (up/down). While these facial expressions and postures are different, since they are reversals of each other, they are similar (as opposed to expressions of anger and surprise, which are much more different expressions). In all these cases the principle of minimal difference allows for binary antonym pairs Within a larger contrast set when two members within the set are perceived to be more similar to one another than to other members of thb set.