Causal Determinism

Of the many types of determinism posited in today’s society, causal determinism is perhaps the most relevant to the scientific, empirical nature of modern life. It is the doctrine that states every event is necessitated by preceding events and the laws of nature, and thus sits well with scientific theory, which also could be said to hold this view of reality. It is an argument opposed to the concept of free will, that mankind has a say in determining its fate and may make choices concerning the future.

This view point is best described through the analogy of Pierre-Simon Laplace in the early 19th century, who devised an argument known as ‘Laplace’s demon’. In this analogy, Laplace postulates that if there were to be a vast consciousness capable of knowing the positions and velocities and understanding the laws of physics, it would be able to determine the future actions of the entirety of the universe. This argument is faced with strong criticism, but not, I believe, insurmountable criticism. One of the crucial major criticisms of determinism that has become progressively more heavily used in the last century is that of the anomalous nature of quantum physics when it comes to future prediction. The Heisenberg uncertainty principle, one of the key tenets of quantum physics, states that the more information known about one aspect of a particle, for example its position, the less that can be known about another aspect i.e. its velocity. This raises problems for the demon because it cannot exactly predict the actions of the particle. However, it could be argued that the field of quantum mechanics is very much an incomplete science and that this uncertainty might perhaps be resolved in the future.

Another opposition argument posited against causal determinism is the existence of ‘Chaos theory’, or the ‘Butterfly effect’. This is the observation that very small irregularities in the original conditions of an experiment can cause large variations in the results, and that these causes are too complex to be determined by the laws of physics. This however can be seen to be a purely anthropological problem. The assumption that because human science is unable to determine the nature of future events, they are not determinable is absurd. It is, I feel, a weak objection to determinism.

A much more credible criticism of the causally deterministic model is perhaps that of the nature of time. Causality depends on the directed and constant flow of time. The assumption that the future can be predicted is based on the knowledge of all that is occurring at time ‘T’, i.e. the time preceding the events you wish to predict. Under a linear, Newtonian model of time and space this would not pose a problem but following the creation of the relativity theories, a constant time frame is no longer guaranteed. Under Einsteinian physics, things do not occur simultaneously across the universe. The continuity of space time is limited by the ‘galactic speed limit’; the speed of light. This does not allow any single observer the possibility of knowing facts about the whole universe simultaneously.

This final objection therefore makes it impossible for the theory of causal determinism to every be verified on the grounds that predictions made by the theory will never be correct, owing to the impossibility of knowing facts about the whole universe which is due to the existence of the speed of light, and the universe’s inherent lack of ‘simultaneousity’, for want of a better term. This however does not mean that the future of the universe is not itself a predetermined fact due to a continuous causal chain. Rather, it simply means if that is the case, we will never know.

Contributed by Isaac Jarratt Barnham

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