by Daniel Ranard.
“Every choice we make is totally predetermined,” you hear someone say, a little too loudly, from a nearby table at the coffee shop. “If we had a big enough supercomputer, and we knew the exact configuration of all the atoms that make up a person and their surroundings, we could calculate their future perfectly!” This sounds like an excited young scientist or amateur futurist. But imagine replacing “supercomputer” with “super-mind,” and it sounds more like the French polymath Laplace, writing about determinism 200 years ago. In fact, as far back as antiquity, you can find philosophers speculating that all motion follows rules.
I imagine that humankind first witnessed the power of this idea when astronomers predicted the motion of the planets, leading to an image of the heavens as an orderly machine. Newton brought the laws of the heavens down to earth, positing that all matter follows the same rules, from celestial bodies to falling rocks. His theories made plausible the image of a clockwork universe, ticking in accordance with mechanical law. At the time, it was difficult or even ridiculous to imagine that living things followed the same rules, and many believed that life had its own spark or guiding force, apart from the mechanistic laws. But advances in biology and chemistry slowly convinced scientists that life is part of the clockwork, too. By the late 1800s, this idea permeated scientific circles and even literature–Dostoevsky's characters raged against the possibility that mathematics determined their decisions.
Since Laplace's time, our physical theories have changed, and our philosophical ideas have grown more sophisticated. With our new knowledge, what could we say to a nineteenth century thinker, existentially worried about living in a clockwork universe? What could we say, for example, to Dostoevsky's “Underground Man” in Notes from the Underground? He's concerned about a world where all human actions are “tabulated according to… laws, mathematically, like tables of logarithms.” Phrasing the question in terms of free will and scientific determinism, many philosophers today declare that there's no need to pick between the two—free will and determinism are compatible. Other philosophers see the compatabilist argument as a mere redefinition of terms. But in addition to the philosophical question, there's also a more scientific question. According to modern scientific theories, is it true that the world behaves mechanistically and allows perfect prediction?