Indeterminism
Indeterminism is the idea that events are not caused, or are not caused deterministically.
It is the opposite of determinism and related to chance. It is highly relevant to the philosophical problem of free will, particularly in the form of metaphysical libertarianism. In science, most specifically quantum theory in physics, indeterminism is the belief that no event is certain and the entire outcome of anything is probabilistic. Heisenberg's uncertainty principle and the "Born rule", proposed by Max Born, are often starting points in support of the indeterministic nature of the universe. Indeterminism is also asserted by Sir Arthur Eddington, and Murray Gell-Mann. Indeterminism has been promoted by the French biologist Jacques Monod's essay "Chance and Necessity".
The physicist-chemist Ilya Prigogine argued for indeterminism in complex systems.
Necessary but insufficient causation
Indeterminists do not have to deny that causes exist. Instead, they can maintain that the only causes that exist are of a type that do not constrain the future to a single course; for instance, they can maintain that only necessary and not sufficient causes exist. The necessary/sufficient distinction works as follows:If x is a necessary cause of y; then the presence of y implies that x definitely preceded it. The presence of x, however, does not imply that y will occur.
If x is a sufficient cause of y, then the presence of y implies that x may have preceded it.
It is possible for everything to have a necessary cause, even while indeterminism holds and the future is open, because a necessary condition does not lead to a single inevitable effect. Indeterministic causation is a proposed possibility, such that "everything has a cause" is not a clear statement of indeterminism.
Probabilistic causation
Interpreting causation as a deterministic relation means that if A causes B, then A must always be followed by B. In this sense, however, war does not always cause deaths, nor does a singular moment of smoking always cause cancer. As a result, many turn to a notion of probabilistic causation. Informally, A probabilistically causes B if AIt can be proved that realizations of any probability distribution other than the uniform one are mathematically equal to applying a function on a random variable following the latter ; the probabilities are contained in the deterministic element. A simple form of demonstrating it would be shooting randomly within a square and then interpreting a relatively large subsquare as the more probable outcome.
Intrinsic indeterminism versus unpredictability
A distinction is generally made between indeterminism and the mere inability to measure the variables. This is especially the case for physical indeterminism. Yet some philosophers have argued that indeterminism and unpredictability are synonymous.Philosophy
Ancient Greek philosophy
Leucippus
The oldest mention of the concept of chance is by the earliest philosopher of atomism, Leucippus, who said:"The cosmos, then, became like a spherical form in this way: the atoms being submitted to a casual and unpredictable movement, quickly and incessantly".
Aristotle
described four possible causes. Aristotle's word for these causes was αἰτίαι, which translates as causes in the sense of the multiple factors responsible for an event. Aristotle did not subscribe to the simplistic "every event has a cause" idea that was to come later.In his Physics and Metaphysics, Aristotle said there were accidents caused by nothing but chance. He noted that he and the early physicists found no place for chance among their causes.
Aristotle opposed his accidental chance to necessity:
Nor is there any definite cause for an accident, but only chance, namely an indefinite cause.
It is obvious that there are principles and causes which are generable and destructible apart from the actual processes of generation and destruction; for if this is not true, everything will be of necessity: that is, if there must necessarily be some cause, other than accidental, of that which is generated and destroyed. Will this be, or not? Yes, if this happens; otherwise not.
Pyrrhonism
The philosopher Sextus Empiricus described the Pyrrhonist position on causes as follows:...we show the existence of causes are plausible, and if those, too, are plausible which prove that it is incorrect to assert the existence of a cause, and if there is no way to give preference to any of these over others – since we have no agreed-upon sign, criterion, or proof, as has been pointed out earlier – then, if we go by the statements of the Dogmatists, it is necessary to suspend judgment about the existence of causes, too, saying that they are no more existent than non-existent
Epicureanism
argued that as atoms moved through the void, there were occasions when they would "swerve" from their otherwise determined paths, thus initiating new causal chains. Epicurus argued that these swerves would allow us to be more responsible for our actions, something impossible if every action was deterministically caused. For Epicureanism, the occasional interventions of arbitrary gods would be preferable to strict determinism.Early modern philosophy
In 1729 theTestament of Jean Meslier states:"The matter, by virtue of its own active force, moves and acts in blind manner".
Soon after Julien Offroy de la Mettrie in his L'Homme Machine. wrote:
"Perhaps, the cause of man's existence is just in existence itself? Perhaps he is by chance thrown in some point of this terrestrial surface without any how and why".
In his Anti-Sénèque we read:
"Then, the chance has thrown us in life".
In the 19th century the French Philosopher Antoine-Augustin Cournot theorized chance in a new way, as series of not-linear causes. He wrote in Essai sur les fondements de nos connaissances :
"It is not because of rarity that the chance is actual. On the contrary, it is because of chance they produce many possible others."
Modern philosophy
Charles Peirce
is a thesis proposed by the American philosopher Charles Sanders Peirce in the 1890s. It holds that absolute chance, also called spontaneity, is a real factor operative in the universe. It may be considered both the direct opposite of Albert Einstein's oft quoted dictum that: "God does not play dice with the universe" and an early philosophical anticipation of Werner Heisenberg's uncertainty principle.Peirce does not, of course, assert that there is no law in the universe. On the contrary, he maintains that an absolutely chance world would be a contradiction and thus impossible.
Complete lack of order is itself a sort of order. The position he advocates is rather that there are in the universe both regularities and irregularities.
Karl Popper comments that Peirce's theory received little contemporary attention, and that other philosophers did not adopt indeterminism until the rise of quantum mechanics.
Arthur Holly Compton
In 1931, Arthur Holly Compton championed the idea of human freedom based on quantum indeterminacy and invented the notion of amplification of microscopic quantum events to bring chance into the macroscopic world. In his somewhat bizarre mechanism, he imagined sticks of dynamite attached to his amplifier, anticipating the Schrödinger's cat paradox.Reacting to criticisms that his ideas made chance the direct cause of our actions, Compton clarified the two-stage nature of his idea in an Atlantic Monthly article in 1955. First there is a range of random possible events, then one adds a determining factor in the act of choice.
A set of known physical conditions is not adequate to specify precisely what a forthcoming event will be. These conditions, insofar as they can be known, define instead a range of possible events from among which some particular event will occur. When one exercises freedom, by his act of choice he is himself adding a factor not supplied by the physical conditions and is thus himself determining what will occur. That he does so is known only to the person himself. From the outside one can see in his act only the working of physical law. It is the inner knowledge that he is in fact doing what he intends to do that tells the actor himself that he is free.
Compton welcomed the rise of indeterminism in 20th century science, writing:
Together with Arthur Eddington in Britain, Compton was one of those rare distinguished physicists in the English speaking world of the late 1920s and throughout the 1930s arguing for the “liberation of free will” with the help of Heisenberg’s indeterminacy principle, but their efforts had been met not only with physical and philosophical criticism but most primarily with fierce political and ideological campaigns.
In my own thinking on this vital subject I am in a much more satisfied state of mind than I could have been at any earlier stage of science. If the statements of the laws of physics were assumed correct, one would have had to suppose that the feeling of freedom is illusory, or if choice were considered effective, that the laws of physics... unreliable. The dilemma has been an uncomfortable one.