A New Time Travel Paradox

It is well-known that time travel into the past, and sometimes also into the future, if it were possible, could give rise to destructive paradoxes. In a previous post I offered a list of five different types of these paradoxes. Here I will explain in more detail the fourth type I mentioned there: the fact that time travel into the past and human freedom are incompatible. I will do so through a short science fiction story, divided into two scenarios.

First scenario

At 3:55 PM, my friend Max said to me, “I just invented a time machine. Do you want to see it?” Of course, I agreed.

At 3:58 PM, Max and I entered the room where the machine was located. It looked like a simple metal chair. The machinery seemed to be under the seat.

The worldview of Louis Pasteur

Louis Pasteur

Louis Pasteur was, without a doubt, one of the greatest scientists of the 19th century. His scientific work was immense. Among his most notable discoveries are the following:

1.      Optical isomerism. The fact that certain substances occur in two different forms, with the same chemical composition but different physical properties, for they rotate the plane of polarization of light in opposite directions.

2.      Alcoholic, acetic, lactic, and butyric fermentations, which he showed are due to the action of bacteria or yeast.

3.      Spontaneous generation, which in his time was only defended for microorganisms, and Pasteur demonstrated it’s impossible under current conditions.

Science and hypothesis

Henri Poincaré

As a scientist, Henri Poincaré was a mathematician who worked in many fields of that science, both theoretical and applied, the latter mainly to physics. Among other things, he achieved a partial solution to the three-body problem and is considered a precursor to chaos theory.

As a philosopher of science, Poincaré was one of the main representatives of the philosophical theory called conventionalism or instrumentalism, which holds that scientific theories are conventional and do not represent reality, but are useful if they can be used to make correct predictions. As I explained in another post, other scientists and philosophers of science, such as Karl Popper, are realists and believe that scientific theories do represent reality, and the more accurately they represent it, the better their predictions will be. Personally, I am not a conventionalist and feel closer to Popper than to Poincaré.

The book by Poincaré that I am going to discuss is titled La Science et l’Hypothèse and was first published in 1902. In this book, with which I obviously disagree, Poincaré defends his instrumentalist ideas.