Deterministic but Unpredictable
A friend and I were discussing Douglas Hofstader’s new book “I Am a Strange Loop”, specifically his comments on Free Will. He tries to dismiss the entire philosophical exercise and focus more on the notion of “choice”, but it seems clear that at a deeper level he ultimately sides with pure determinism. This appears to be the emerging consensus of the scientific community as shown in this poll of “professional evolutionary scientists.” (Overall Hofstader’s book was a bit disappointing and somewhat derivative of his earlier work.)
At a spiritual level, it can be unnerving to think that all of one’s actions are, in essence, predetermined and could in principal be predicted if the initial conditions were known with enough accuracy. Henri Poincaré’s work on the famous 3-body problem though demonstrated over a hundred years ago that it is impossible to ever approach such a calculation—things may be deterministic but they are unpredictable.
Two other books that I recently read, Ivar Ekeland’s book “Mathematics and the Unexpected” and Nassim Nicholas Taleb’s snarky “The Black Swan” both deal in their own way with implications of unpredictability and discuss Poincaré’s work. Coincidentally both books highlight this difficulty by referencing the same detail from a 1978 paper by Professor Michael Berry called “Regular and Irregular Motion” which analyzed Poincaré’s insights in great detail.
On page 95 of that paper, Berry calculates that, given a billiard table, after only 9 collisions, in order to make a accurate prediction of the final state, the gravitational effects of the people in the room would need to be taken into account. After 56 collisions, the effects of a single electron at the edge of the visible universe would be required!