Laplace's Demon Essay Example

For generations, Laplace's views have dominated different understandings of probability. In fact, our account of various interpretations of probability would not be complete without acknowledging classical interpretations of probabilities by Pierre-Simon Laplace in his popular book Philosophical Essays on Probabilities, first published in 1814. Laplace's demon was the first articulation of causal determinism. Notably, Laplace used the word "intellect" and not "demon". The word "demon" was only added later for effect. He promoted the Bayes' theorem, the mathematical formula that explains the probability of a given event based on some pre-existing knowledge of states related to that event. Determinism, the basis of Laplace's demon, is the idea that every detail of the present event is caused by a preceding event and conditions of nature. If you know the present quantum mechanical state of all the particles in the universe, you can then determine their past and future details. He believed that if a demon that has perfect knowledge of the present state, knowing all the activities of the past and rules of causality, then it can predict the future.

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Laplacian determinism has a combination of these three principles: predictability, determinism and explanatory adequacy of scientific laws and conditions. It is applied in celestial mechanics and scientific theories whose logic cannot questionable. These principles imply reducibility and close out holism and emergence. Laplacian determinism, however, fails in planetary dynamics and does not give a proper explanatory success (Collier, 2013).

At first, the demon was viewed by scientists as a symbol of the ultimate goal of science; the truth. They thought that it was just a matter of time before humanity unveiled all the secrets of the universe. The first blow to the Laplace demon was the second law of thermodynamics which states that there is no way the total amount of energy of any remote system can reduce over time. This implied that the universe automatically degenerates into a more disordered state over time (Fierro, 2017).

In Laplace's vision, for you to determine the future of particles in the universe, you have to know their positions and velocities at a certain time. Weiner Heisenberg pointed out that is difficult to determine the exact positions and velocities of the particles (Hawking, 1999). Heisenberg formulated the Uncertainty Principle that states that the exact position and speed of an object at a given cannot be defined. This makes it difficult to get the future probability of the particles. The wave equation contains all the properties of a particle. Given a wave equation at a particular time, you can use the Schrodinger's equation to determine the values at other times (Hawking, 1999). But this is not the kind of determinism that Laplace had in mind. His idea was that instead of predicting the positions and velocities of the particles on the wave, we can only predict the wave function.

The Laplace demon concept has been used in revising probability values when making decisions. In business, for example, it is able to make the most accurate predictions possible based on a set of facts. Unlike simple probability that makes predictions on unrelated events, it allows us to make predictions on related events. It also controls false positives. The health sector uses it to calculate the chance that someone identified as a positive match by a test is likely to be a false negative (Newton, 2018). However, when it is difficult to choose a sensible prior, the methods can give dubious predictions.

In the spectacles of Laplace's philosophy chance are an illusion of the mind and an expression of human ignorance. Under the principle of sufficient reason, Pierre-Simon argues that present events are connected with past events by a justification based upon the evident assumption that a thing cannot happen without a probable cause that produces it. Founded on the dominant philosophy of determinism, Laplace's demon asserts that lack of knowledge is the cause of uncertainties. Causal determinism states that every single event occurs with a reason which is inevitably followed by the event. Epistemological determinism, on the other hand, states that, if people had enough knowledge it would be possible to accurately predict the entire future of the universe at any given point in time.

The concept of Laplace's demon is one that allows us to use classical mechanics to predict the future of the universe. It is some kind of super-intelligence in which people could accurately predict the positions of forces and velocities in all particles of the universe while having enough powerful reasoning, thus being able to determine previous and subsequent values and the state of everything using the laws of classical mechanics. Ideally, Pierre-Simon's concept was based on the principles of classical mechanics and reversibility with the assumption that the past, present and future have the exact amount of information. However, Karl Popper disagrees with that kind of reasoning and observes that no matter how complete information is provided to the demon regarding the past and future state questions will always arise about its own future state which cannot be answered by the demon. Karl Pooper's philosophy of non-self predictability states that it is not possible for any observer to predict the entire states of the system in which they exist. As such, the universe can only be epistemologically deterministic for external entities such as God.

Laplace's philosophy expresses the idea that natural phenomena obey scientific laws. This is the origin of the concept of scientific determinism. According to scientific determinism, it is possible to know the precise momentum and location of individual atoms in the universe while predicting their past and future values through calculations from classical mechanics. This eliminates the idea that free will is possible in a deterministic world. Critics of free will argue that if human actions cannot be casually determined then, there is a possibility that they occur by chance. This is like saying because I fed my cat at 8.00pm; I will always be doing that. This outcome might be true today, just as it was years ago or years to come. Looking at this scenario, it is possible to argue that even though I had free will to feed my cat at any other given time, granted determinism made it logically impossible. This means I was fated to act the way I did.

Focusing on the concept of quantum physics, I am convinced that the future is more predictable in a probabilistic universe that it is in a deterministic universe. Generally, casual determinism explains how particular activities occur without giving details about their specific causes. Furthermore, it does not prove that the factors that have caused or are causing the activity to occur are predictable with any given degree of certainty. If truth be told, suppose the presumptions of causal determinism are put to its logical conclusion, it is impossible for Laplace's demon to predict the totality of past and future activities because they have never coalesced.

The errors of Laplace's demon hypothesis can be mirrored through the concept of Heisenberg's Uncertainty Principle also referred to as Quantum mechanics. Heisenberg's Uncertainty Principle asserts that it is impossible to measure with absolute accuracy the locus and momentum of a particle because the more accurate one knows the values; the less accurate one is able to know the other values. In other words, Karl Heisenberg says that it is not possible to predict all future activities with scientific certainty, even with assumed perfect knowledge of all past activities and their causes. Critics of Laplace's demon have argued that quantum logic exposes the flaws in casual determinism which is the main tenet of Laplace's philosophy because it argues that entirety of historical information cannot be used to predict the future with certainty because two identical particles subjected to same causes might behave differently.

From a scientific perspective, the theoretical possibility of Laplace's demon philosophy challenges our conceptualization of basic observation. Quantum mechanics contradicts hidden variables which would make the concept deterministic to allow past and future activities to be visible in the demon's eyes. Literally, observation rules out the occurrence of hidden variables to prevent violation of Bell's inequality. Also given that time cannot be separated from other elements, one can argue from the point of nonlocality that the entire knowledge of previous and upcoming events of the universe may not require part of its history to be lost.

The fact that people do not know a lot of things is the idea behind probabilities. Laplace's demon has an omniscient knowledge of reality. By simply analyzing the state of the universe the demon has the capability of determining any future event. Many scientists have argued that for all practical purposes the demon can never exist in the real world. This is because there is an infinite amount of information to account for. Even with the most sophisticated computer technology, it is not possible to ascertain the state and force of every particle at all times. Laplace demon is nothing far from an all knowing and all powerful Supreme Being. However, Popper perceives the demon as firmly belonging to the real world and part of a system that is supposed to give accurate predictions.

Apparently, Pierre-Simon was not the only person in history to evoke the demon philosophy. In 1867, James Clerk suggested how the second law of thermodynamics might be violated hypothetically. His thought experiment is famously known as Maxwell's demon. Maxwell's philosophy works by converting knowledge of particles' location and velocity into work. Maxwell's demon is demonstrated in Leo Szilard experiment where a container is divided into two by a shutter. Two pistons are connected from each end of the partitions.

Source:

• In (I) the demon is not aware of the molecule position. The hole in the partition remains closed and the molecule exists in either side.
• In (II) the demon locates the molecule in one side (left) and is the only information available.
• In (III) the demon pushes the piston on the right until it reaches the centre. Given that no pressure is acting against the piston, no work is required.
• The demon then opens the hole in as illustrated in (IV). The pressure exerted on the right side is higher than the pressure on the left so the particle is moved right and energy could be extracted from it.
• The cycle is repeated from the first step in (V). Here, the hole is open and the demon is not aware which side of the partition the molecule will be residing at any given moment.

When Laplace's and Maxwell's demons come together they complement each other (Weinert, 2016). When this happens, Maxwell's demon will no longer need to measure the portion of the container in which the molecule is located in. Instead, Laplace's demon will provide information on which direction to move the shutter. When Maxwell's demon fails to store information regarding the location of the molecule a memory loss occurs which causes a violation of the second law of thermodynamics. By introducing a demon, Maxwell assumes that the partitions are no longer a closed system. The entropy of the partitions decreases because the demon increases its entropy.

Conclusion

Laplace's philosophy suggests two arguments for its views that our actions are not free. First, Laplace points out that all things work according to the laws of nature (chemical, physical, biological or psychological) that determine how everything operates. Secondly, he asserts that all events must have a cause that produces them. One can, therefore, argue that if human actio...