Tree vs human. Photo by Gilly Stewart on Unsplash.

Milton Friedman and the surprising rationality of trees

In one of the most famous essays of 20th century economics, one of its most famous protagonists offers an astounding hypothesis on tree growth, just to dismiss it out of hand. Indeed, the dismissal is understood to be mutual between author and reader, as it sets up the author’s intellectual tour de force.

Consider the density of leaves around a tree. I suggest the hypothesis that the leaves are positioned as if each leaf deliberately sought to maximize the amount of sunlight it receives, given the position of its neighbors, as if it knew the physical laws determining the amount of sunlight that would be received in various positions and could move rapidly or instantaneously from any one position to any other desired and unoccupied position. Now some of the more obvious implications of this hypothesis are clearly consistent with experience: for example, leaves are in general denser on the south than on the north side of trees but, as the hypothesis implies, less so or not at all on the northern slope of a hill or when the south side of the trees is shaded in some other way. Is the hypothesis rendered unacceptable or invalid because, so far as we know, leaves do not “deliberate” or consciously “seek,” have not been to school and learned the relevant laws of science or the mathematics required to calculate the “optimum” position, and cannot move from position to position?

— Milton Friedman, The Methodology of Positive Economics, 1953.

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Strategic trees and the seat of rationality

The hedonistic conception of man is that of a lightning calculator of pleasures and pains who oscillates like a homogeneous globule of desire of happiness under the impulse of stimuli that shift him about the area, but leave him intact. — Thorstein Veblen, Why is Economics Not an Evolutionary Science, 1898.

I write about how technology shapes the world we live in.