The future is not written

In several posts in this blog, I've discussed determinism, always from a critical perspective. For example, in a post entitled The debacle of determinism, I mentioned the three devastating attacks suffered by determinism during the 20th century: Heisenberg's uncertainty principle (although it would be better to use the name Heisenberg originally proposed: the indeterminacy principle); chaos theory; and the Copenhagen interpretation of quantum mechanics.

Chapter 7 of Kevin Mitchell's book Free Agents, titled, like this post, The future is not written, analyzes and refutes determinism. However, it doesn't discuss just one type of determinism, but three, refuting them one after another in successive chapters. What are these three types of determinism?

1.      Physical predeterminism: the idea that only one possible timeline exists. In other words, that the future is entirely determined by the past; that the entire history of the universe is predetermined from the beginning; that nothing that happens could have happened otherwise.

Determinism or indeterminism?

Modern science has revolutionized our vision of the world. In the eighteenth century, Newton's theory of gravitation could be considered established, and gave rise to a materialistic-deterministic vision of the universe which can be personified in one of the most significant scientists of the time, Pierre-Simon, Marquis de Laplace (1749-1827), whose fields of study covered mathematics, astronomy, chemistry and biology. The success of his studies on the dynamics of the solar system moved him to state that, if we knew the exact initial conditions of the universe, it would be possible to predict all its past and future development. This gave rise to materialistic determinism, so successful in the nineteenth century and still a part of the popular vision of the world, in spite of the three devastating attacks it has suffered during the twentieth century.

The debacle of determinism

Isaac Newton

By the end of the eighteenth century, Isaac Newton’s theory of universal gravitation was well established. As this theory makes it possible to predict very accurately the orbits of the bodies in the solar system, the French astronomer Pierre Simon de Laplace believed he had sufficient reasons to say the following:

An intelligence that knew all the forces that animate nature, as well as the respective situation of the beings that make it... could cover in a single formula the movements of the largest bodies of the universe and those of the lighter atom. Nothing would be uncertain and both the future and the past would be present before his eyes.

This assertion became the dogma of deterministic materialism, a philosophical (not scientific) doctrine asserting that only matter exists (taking the term broadly) and that the whole history of the universe is determined. Therefore there is no human freedom, nor intentionality, nor final causes in nature. There are just efficient causes.

Laplace’s statement can be expressed in more modern terms:

If we knew the position and the momentum of all the particles of the universe at a given instant, we could predict all their past and future development.