Thread: Determinism Logically Refuted

Unfinished
Saving thread so that I don't lose everything, since I'm on a work computer. Feel free to comment but there is a whole shit load of more information that still needs to go in here.

Introduction

A very good definition for determinism, given by the Stanford Encyclopedia of Philosophy is stated as,

"Determinism: The world is governed by (or is under the sway of) determinism if and only if, given a specified way things are at a time t, the way things go thereafter is fixed as a matter of natural law."

I am going to do my best to attempt to show two things. The first thing I am going to attempt to show is that given a specified way things are at a time t, multiple outcomes are possible, and the second thing I am going to attempt to show is that it is perhaps even impossible to conclusively prove that the idea of a 'specified way things are' is even a valid concept. I will do my best to present my arguments in a clear and ordered way so that it is easy to understand. I will also do my best to segment my argument in to clear parts so that one can skip over the concepts that he or she is already familiar with/ can't be arsed to read about.

A common belief held by those that believe in a deterministic universe was best summed up by A french Philosopher named Pierre-Simon, marquis de Laplace. He said that,

"We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes."(Laplace, Essai philosophique, 1814)

It seems as though this is a logical belief based on what we know about the world, and indeed it is if we only take classical physics in to account (which is all that was known to Laplace at the time.) Unfortunately, relatively recent theoretical and experimental progress in the fields of mathematics and Quantum Mechanics have shown this claim to be definitely false as far as our understanding as humans is concerned.

In the sections that follow I will outline the concepts of the General Uncertainty Principle, Chaos Theory, Superpositions/Wave-Particle duality, Quantum Entanglement, and Quantum Foam. The emperically verified ideas behind the General Uncertainty Principle alone are enough to disprove Laplace's claim, but I believe the conjuction of all of these topics can be used to significantly undermine the theory of determinism as a whole. Each of these subjects are weigthy in themselves, but I will do my best to briefly outline them one by one so that anyone who cares to read will have a better understanding of what I am trying to portray.

General Uncertainty Principle

Because it is the easiest way to show Laplace's claim to be false, I will begin with Uncertainty.

The Uncertainty Principle was originally introduced by German physicist Werner Heisenberg in 1927, which is why it is often refered to as Heisenberg's Uncertainty Principle. He discovered the concept while examining experimental measurements of the positions and momentums of electrons. The positions of electrons are measured by firing photons at them and then observing how the photons are scattered (otherwise known as "shining a light on them") Unfortunately, the photon rebounding off of the electron causes a change in the electrons momentum. The shorter the wavelength of light that is used to observe the electron, the more precise the measurement of its position will be, but shorter wavelengths carry more energy and so will have a larger and less predictable effect on the electrons momentum. This is the beginning of the basic relationship between the position and momentum of an electron in which the more precisely the position is defined, the more poorly the momentum will be defined and vice versa.

It has been found that this phenomenon isn't even due to the actual measurements being taken and is intrinsic in the behavior of the electron. Even if you were to conduct an experiment in which many particles are set up in a similar fashion so that they can be said to be identical (are in the same quantum states) and then measured the position of half of them and the momentum of half of them you would find the same relationship. The group in which you measured the position would give an array of results and from this you could find the standard deviation, which is the average variation from the mean position, and the same would be true for the momentum. The smaller the standard deviation found in the position group, the larger the deviation would be in the momentum group. Heisenberg summed this up by saying, "This indeterminateness is to be considered an essential characteristic of the electron, and not as evidence of the inapplicability of the wave picture."

Since Heisenberg, other physicists have discovered that this relationship applies to many pairs of characteristics of quantum states and not only position and momentum.

What this all means for Laplace is that no being could possibly know every aspect of the movements and the position of all that exists in the universe at any given point in time, and so his interpretation of determinism is false, and at the very least determinism is ill equipped to make accurate predictions about the state of the entirity of any system at any given point in time.

Wave-Particle Duality

Quantum Entanglement

Quantum Foam

Chaos Theory


Bibliography

I've included several sources on these topics in order to make sure I used the correct dates and names, and also so that anyone who is interested can read some more indepth descriptions and check the validity of the concepts I've outlined above.

The Uncertainty Principle, Stanford Encyclopedia of Philosophy
Causal Determinism, Stanford Encyclopedia of Philosophy
Feynmen Double Slit experiment
Chaos Theory, a brief Introduction
Quantum Foam, New Scientist 19 June 1999
Wheeler's Delayed Choice Experiment, Ross Rhodes