Nutrition science is where surgery was in about 1650, you know, really interesting and promising, but would you want to have them operate on you yet?… - Michael Pollan

Christianity and capitalism are both probably right to detest a plant like cannabis. Both faiths bid us to set our sights on the future; both reject the pleasures of the moment and the senses in favor of the expectation of a fulfillment yet to come—whether by earning salvation or by getting and spending. More even than most plant drugs, cannabis, by immersing us in the present and offering something like fulfillment here and now, short-circuits the metaphysics of desire on which Christianity and capitalism (and so much else in our civilization) depend.

The Greeks believed that true beauty (as opposed to mere prettiness) was the offspring of these two opposing tendencies, which they personified in Apollo and Dionysus, their two gods of art. Great art is born when Apollonian form and Dionysian ecstasy are held in balance, when our dreams of order and abandon come together. One tendency uninformed by the other can bring forth only coldness or chaos—the stiffness of a Triumph tulip, the slackness of a wild rose.

Beauty and nature often shows up in the vicinity of sex—think of the plumage of birds or mating rituals through out the animal kingdom. “Sexual selection”—that is, evolution’s favoring of features that increase a plant’s or animal’s attractiveness and therefore it's reproductive success—is the best explanation we have for the otherwise senseless extravagance of feathers and flowers, maybe also sports cars and bikinis. In nature, at least, the expense of beauty is usually paid for by sex.
There may or may not be a correlation between the beautiful and the good, but there probably is one between beauty and health. (Which, I suppose, in Darwinian terms, is the good.) Evolutionary biologists believe that in many creatures beauty is a reliable indicator of health, and therefore a perfectly sensible way to choose one mate over another. Gorgeous plumage, lustrous hair, symmetrical features are “certificates of health,” as one scientist puts it, advertisements that a creature carries genes for resistance to parasites and is not otherwise under stress. A fabulous tail is a metabolic extravagance only the healthy can afford.