Scientific Models and Individual Experience

by David Kordahl

I’ll start this column with an over-generalization. Speaking roughly, scientific models can be classed into two categories: mechanical models, and actuarial models. Engineers and physical scientists tend to favor mechanical models, where the root causes of various effects are specified by their formalism. Predictable inputs, in such models, lead to predictable outputs. Biologists and social scientists, on the other hand, tend to favor actuarial models, which can move from measurements to inferences without positing secret causes along the way. By calling these latter models “actuarial,” I’m encouraging readers to think of the tabulations of insurance analysts, who have learned to appreciate that individuals may be unpredictable, even as they follow predictable patterns in the aggregate.

Operationally, these categories refer to different scientific practices. What I’ve called a difference between mechanical vs. actuarial models could just as well be sketched as a difference between theory-driven vs. data-driven models. Both strains have coexisted in science for the past few centuries.

Just for fun, we might attempt to caricature the history of modern science in the mechanical vs. actuarial terms introduced above. In the seventeenth century, Isaac Newton proposed a law of universal gravitation, applicable everywhere throughout the universe, which allowed naturalists to imagine that all physical effects, everywhere and for all time, were caused by physical laws, just waiting to be discovered. This view was developed to its philosophical extreme in the eighteenth century by the French mathematician, Pierre Laplace, who imagined that the universe at any particular moment implicitly contained the specifications for its entire past and future.

But in the nineteenth century, Charles Darwin introduced his theory of natural selection, which allowed naturalists to take actuarial models more seriously. Just as hidden order could cause the appearance of randomness, hidden randomness could cause the appearance of order. Read more »

The Meaning of Apples

by Emrys Westacott

What is it about the apple? Common, easily grown, and cheap to buy, yet when you think about it the apple is a major character in the history of our culture. Apple-191004_150It pops up continually to play significant roles in religion, mythology, science, and the arts, and remains metaphorically active in everyday language.

The first example that comes to mind, of course, is the apple that Adam and Eve partook of in the garden of Eden, thereby precipitating the Fall thanks to which we now have to toil among thorns and thistles, earning our bread in the sweat of our brow instead of lounging around in paradise. Scholars and pedants will immediately point out that the bible doesn't say that what Eve plucked from the tree of knowledge was actually an apple: it just describes it rather vaguely as the tree's fruit. Since there was only ever one tree of knowledge, it quite likely produced a unique fruit that is no longer available, not even at Whole Foods. But that's beside the point. In the popular mind Eve bit into an apple, thought it tasted good (so we know it wasn't some mealy Golden Delicious) and offered it to Adam; he took a bite, and the rest is a lot more mythology eventually feeding into history. Size1Here the dual character of the apple is revealed for the first time. As coming from the tree of knowledge it's presumably good, knowledge itself being a fine thing. But since eating it is sinful, the initial sweetness turns bitter, and what at first gives delight leads to shame, exile, labour and death.

It was also an apple that set in motion the events leading to the Trojan War, tragic and glorious in equal measure according to our primary source. The wedding of Peleus and Thetis had an impressive guest list that included all the Olympian gods but not Eris (a.k.a. Discordia) goddess of Chaos and Strife. She wasn't invited for obvious reasons, but she came anyway and true to form tossed into the midst of the revelers a golden apple inscribed, “To the fairest.” Hera, Athena, and Aphrodite all claimed it; Zeus appointed Paris, a prince of Troy, to decide who should have it; Aphrodite offered the best bribe—the beautiful Helen of Sparta—so she got the apple, Paris got Helen, and Troy got razed to the ground after a ten-year war. In this case, too, the apple's outward appeal–it is brilliant, beautiful, and desired by three goddesses–hides a dark core that breeds rivalry, envy, seduction, betrayal, war, and destruction.

Read more »