Indeterminism is the idea that
events (or certain events, or events of certain types) 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
Free will is generally understood as the capacity or ability of people to (a) choice, choose between different possible courses of Action (philosophy), action, (b) exercise control over their actions in a way that is necessary for moral respon ...
, particularly in the form of metaphysical
libertarianism
Libertarianism (from ; or from ) is a political philosophy that holds freedom, personal sovereignty, and liberty as primary values. Many libertarians believe that the concept of freedom is in accord with the Non-Aggression Principle, according t ...
. In
science
Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which stu ...
, most specifically
quantum theory in
physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
, 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
A complex system is a system composed of many components that may interact with one another. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communication s ...
.
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. (However, another cause ''z'' may alternatively cause ''y''. Thus the presence of ''y'' does not imply the presence of ''x'', or ''z'', or any other suspect.)
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 (or probabilistic) 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 (see
Cyberwarfare
Cyberwarfare is the use of cyberattack, cyber attacks against an enemy State (polity), state, causing comparable harm to actual warfare and/or disrupting vital computer systems. Some intended outcomes could be espionage, sabotage, propaganda, ...
), nor does a singular moment of
smoking
Smoking is a practice in which a substance is combusted, and the resulting smoke is typically inhaled to be tasted and absorbed into the bloodstream of a person. Most commonly, the substance used is the dried leaves of the tobacco plant, whi ...
always cause
cancer
Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...
. As a result, many turn to a notion of
probabilistic causation. Informally, ''A'' probabilistically causes ''B'' if ''A''
's occurrence increases the probability of ''B''. This is sometimes interpreted to reflect the imperfect knowledge of a deterministic system but other times interpreted to mean that the causal system under study has an inherently indeterministic nature. (
Propensity probability is an analogous idea, according to which probabilities have an objective existence and are not just limitations in a subject's knowledge).
It can be proved that realizations of any
probability distribution
In probability theory and statistics, a probability distribution is a Function (mathematics), function that gives the probabilities of occurrence of possible events for an Experiment (probability theory), experiment. It is a mathematical descri ...
other than the
uniform
A uniform is a variety of costume worn by members of an organization while usually participating in that organization's activity. Modern uniforms are most often worn by armed forces and paramilitary organizations such as police, emergency serv ...
one are mathematically equal to applying a (deterministic) function (namely, an
inverse distribution function) on a random variable following the latter (i.e. an "absolutely random" one); the probabilities are contained in the deterministic element. A simple form of demonstrating it would be shooting randomly within a square and then (deterministically) 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 (limits of precision). This is especially the case for physical indeterminism (as proposed by various
interpretations of quantum mechanics). 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
Aristotle
Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...
described four possible causes (material, efficient, formal, and final). Aristotle's word for these causes was αἰτίαι (''aitiai'', as in ''
aetiology''), 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 (single) cause" idea that was to come later.
In his ''
Physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
'' and ''
Metaphysics
Metaphysics is the branch of philosophy that examines the basic structure of reality. It is traditionally seen as the study of mind-independent features of the world, but some theorists view it as an inquiry into the conceptual framework of ...
'', Aristotle said there were
accidents (συμβεβηκός, ''
sumbebekos'') caused by nothing but chance (τύχη, ''tukhe''). 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 (τυχόν), namely an indefinite (ἀόριστον) 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
Epicurus
Epicurus (, ; ; 341–270 BC) was an Greek philosophy, ancient Greek philosopher who founded Epicureanism, a highly influential school of philosophy that asserted that philosophy's purpose is to attain as well as to help others attain tranqui ...
argued that as atoms moved through the void, there were occasions when they would "swerve" (''
clinamen'') 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 the
''Testament'' of
Jean Meslier
Jean Meslier (; also Mellier; 15 June 1664 – 17 June 1729) was a French Catholic priest (abbé) who was discovered, upon his death, to have written a book-length philosophical essay promoting atheism and materialism. Described by the author as ...
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.'' (1748, anon.) 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''
'Traité de la vie heureuse, par Sénèque, avec un Discours du traducteur sur le même sujet'', 1750we 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'' (1851):
"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
Tychism ( "chance") is a thesis proposed by the American philosopher
Charles Sanders Peirce
Charles Sanders Peirce ( ; September 10, 1839 – April 19, 1914) was an American scientist, mathematician, logician, and philosopher who is sometimes known as "the father of pragmatism". According to philosopher Paul Weiss (philosopher), Paul ...
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
Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ...
's oft quoted dictum that: "
God does not play dice with the universe" and an early philosophical anticipation of
Werner Heisenberg
Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II.
He pub ...
's
uncertainty principle
The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position a ...
.
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
Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the ...
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 choice is the range of different things from which a being can choose. The arrival at a choice may incorporate Motivation, motivators and Choice modelling, models.
Freedom of choice is generally cherished, whereas a severely limited or arti ...
.
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:
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 (as did most philosophers) that the feeling of freedom is illusory, or if reechoice were considered effective, that the laws of physics ... ereunreliable. The dilemma has been an uncomfortable one.
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.
Karl Popper
In his essay ''Of Clouds and Clocks'', included in his book ''Objective Knowledge'',
Popper
contrasted "clouds", his metaphor for indeterministic systems, with "clocks", meaning deterministic ones.
He sided with indeterminism, writing
I believe Peirce was right in holding that all clocks are clouds to some considerable degree — even the most precise of clocks. This, I think, is the most important inversion of the mistaken determinist view that all clouds are clocks
Popper was also a promoter of
propensity probability.
Robert Kane
Kane is one of the leading contemporary philosophers on
free will
Free will is generally understood as the capacity or ability of people to (a) choice, choose between different possible courses of Action (philosophy), action, (b) exercise control over their actions in a way that is necessary for moral respon ...
.
[Kane, R. (ed.) ''Oxford Handbook of Free Will''] Advocating what is termed within philosophical circles "
libertarian freedom", Kane argues that "(1) the existence of alternative possibilities (or the agent's power to do otherwise) is a necessary condition for acting freely, and (2) determinism is not compatible with alternative possibilities (it precludes the power to do otherwise)". It is important to note that the crux of Kane's position is grounded not in a defense of alternative possibilities (AP) but in the notion of what Kane refers to as ultimate responsibility (UR). Thus, AP is a necessary but insufficient criterion for free will. It is necessary that there be (
metaphysically) real alternatives for our actions, but that is not enough; our actions could be random without being in our control. The control is found in "ultimate responsibility".
What allows for ultimate responsibility of creation in Kane's picture are what he refers to as "self-forming actions" or SFAs — those moments of indecision during which people experience conflicting wills. These SFAs are the undetermined, regress-stopping voluntary actions or refrainings in the life histories of agents that are required for UR. UR does not require that ''every'' act done of our own free will be undetermined and thus that, for every act or choice, we could have done otherwise; it requires only that certain of our choices and actions be undetermined (and thus that we could have done otherwise), namely SFAs. These form our character or nature; they inform our future choices, reasons and motivations in action. If a person has had the opportunity to make a character-forming decision (SFA), he is responsible for the actions that are a result of his character.
Mark Balaguer
Mark Balaguer, in his book ''Free Will as an Open Scientific Problem'' argues similarly to Kane. He believes that, conceptually, free will requires indeterminism, and the question of whether the brain behaves indeterministically is open to further
empirical
Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law.
There is no general agreement on how t ...
research. He has also written on this matter "A Scientifically Reputable Version of Indeterministic Libertarian Free Will".
Science
Mathematics
In
probability theory
Probability theory or probability calculus is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expre ...
, a
stochastic process
In probability theory and related fields, a stochastic () or random process is a mathematical object usually defined as a family of random variables in a probability space, where the index of the family often has the interpretation of time. Sto ...
, or sometimes random process, is the counterpart to a deterministic process (or
deterministic system). Instead of dealing with only one possible reality of how the process might evolve over time (as is the case, for example, for solutions of an
ordinary differential equation
In mathematics, an ordinary differential equation (ODE) is a differential equation (DE) dependent on only a single independent variable (mathematics), variable. As with any other DE, its unknown(s) consists of one (or more) Function (mathematic ...
), in a stochastic or random process there is some indeterminacy in its future evolution described by probability distributions. This means that even if the initial condition (or starting point) is known, there are many possibilities the process might go to, but some paths may be more probable and others less so.
Classical and relativistic physics
The idea that
Newtonian physics proved causal determinism was highly influential in the early modern period.
"Thus physical determinism
.became the ruling faith among enlightened men; and everybody who did not embrace this new faith was held to be an obscurantist and a reactionary". However: "Newton himself may be counted among the few dissenters, for he regarded the solar system as ''imperfect'', and consequently as likely to perish".
Classical chaos is not usually considered an example of indeterminism, as it can occur in deterministic systems such as the
three-body problem.
John Earman has argued that most physical theories are indeterministic. For instance, Newtonian physics admits solutions where particles accelerate continuously, heading out towards infinity. By the
time reversibility
In mathematics and physics, time-reversibility is the property (mathematics), property of a process whose governing rules remain unchanged when the direction of its sequence of actions is reversed.
A deterministic process is time-reversible if th ...
of the laws in question, particles could also head inwards, unprompted by any pre-existing state. He calls such hypothetical particles "
space invaders
is a 1978 shoot 'em up video game developed and published by Taito for Arcade video game, arcades. It was released in Japan in April 1978, with the game being released by Midway Manufacturing overseas. ''Space Invaders'' was the first fixed s ...
".
John D. Norton has suggested another indeterministic scenario, known as
Norton's Dome, where a particle is initially situated on the exact apex of a dome.
Branching space-time is a theory uniting indeterminism and the
special theory of relativity. The idea was originated by
Nuel Belnap. The equations of
general relativity
General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...
admit of both indeterministic and deterministic solutions.
Boltzmann
Ludwig Boltzmann
Ludwig Eduard Boltzmann ( ; ; 20 February 1844 – 5 September 1906) was an Austrian mathematician and Theoretical physics, theoretical physicist. His greatest achievements were the development of statistical mechanics and the statistical ex ...
was one of the founders of
statistical mechanics
In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. Sometimes called statistical physics or statistical thermodynamics, its applicati ...
and the modern
atomic theory of matter. He is remembered for his discovery that the
second law of thermodynamics
The second law of thermodynamics is a physical law based on Universal (metaphysics), universal empirical observation concerning heat and Energy transformation, energy interconversions. A simple statement of the law is that heat always flows spont ...
is a statistical law stemming from
disorder. He also speculated that the ordered universe is only a small bubble in a larger sea of chaos. The
Boltzmann brain is a similar idea.
Evolution and biology
Darwinian evolution has an enhanced reliance on the chance element of
random mutation compared to the earlier evolutionary theory of
Herbert Spencer
Herbert Spencer (27 April 1820 – 8 December 1903) was an English polymath active as a philosopher, psychologist, biologist, sociologist, and anthropologist. Spencer originated the expression "survival of the fittest", which he coined in '' ...
. However, the question of whether evolution requires genuine ontological indeterminism is open to debate
In the essay ''
Chance and Necessity'' (1970) Jacques Monod rejected the role of
final causation in
biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
, instead arguing that a mixture of
efficient causation and "pure chance" lead to
teleonomy, or merely ''apparent'' purposefulness.
The Japanese theoretical population geneticist
Motoo Kimura emphasises the role of indeterminism in evolution. According to
neutral theory of molecular evolution: "at the molecular level most evolutionary change is caused by
random drift of
gene mutants that are equivalent in the face of selection.
Prigogine
In his 1997 book, ''The End of Certainty'', Prigogine contends that determinism is no longer a viable scientific belief. "The more we know about our universe, the more difficult it becomes to believe in determinism." This is a major departure from the approach of
Newton,
Einstein and
Schrödinger, all of whom expressed their theories in terms of deterministic equations. According to Prigogine, determinism loses its explanatory power in the face of
irreversibility and
instability.
Prigogine traces the dispute over determinism back to
Darwin, whose attempt to explain individual variability according to evolving populations inspired
Ludwig Boltzmann
Ludwig Eduard Boltzmann ( ; ; 20 February 1844 – 5 September 1906) was an Austrian mathematician and Theoretical physics, theoretical physicist. His greatest achievements were the development of statistical mechanics and the statistical ex ...
to explain the behavior of gases in terms of populations of particles rather than individual particles. This led to the field of
statistical mechanics
In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. Sometimes called statistical physics or statistical thermodynamics, its applicati ...
and the realization that gases undergo irreversible processes. In deterministic physics, all processes are time-reversible, meaning that they can proceed backward as well as forward through time. As Prigogine explains, determinism is fundamentally a denial of the
arrow of time. With no arrow of time, there is no longer a privileged moment known as the "present," which follows a determined "past" and precedes an undetermined "future." All of time is simply given, with the future as determined or undetermined as the past. With irreversibility, the arrow of time is reintroduced to physics. Prigogine notes numerous examples of irreversibility, including
diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...
,
radioactive decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...
,
solar radiation
Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible light perceptible to the human eye as well as invisible infrared (typically p ...
,
weather
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmo ...
and the emergence and evolution of
life
Life, also known as biota, refers to matter that has biological processes, such as Cell signaling, signaling and self-sustaining processes. It is defined descriptively by the capacity for homeostasis, Structure#Biological, organisation, met ...
. Like weather systems, organisms are unstable systems existing far from
thermodynamic equilibrium. Instability resists standard deterministic explanation. Instead, due to sensitivity to initial conditions, unstable systems can only be explained statistically, that is, in terms of
probability
Probability is a branch of mathematics and statistics concerning events and numerical descriptions of how likely they are to occur. The probability of an event is a number between 0 and 1; the larger the probability, the more likely an e ...
.
Prigogine asserts that
Newtonian physics has now been "extended" three times, first with the use of the wave function in
quantum mechanics
Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...
, then with the introduction of spacetime in
general relativity
General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...
and finally with the recognition of indeterminism in the study of unstable systems.
Quantum mechanics
At one time, it was assumed in the physical sciences that if the behavior observed in a system cannot be predicted, the problem is due to lack of fine-grained information, so that a sufficiently detailed investigation would eventually result in a deterministic theory ("If you knew exactly all the forces acting on the dice, you would be able to predict which number comes up").
However, the advent of
quantum mechanics
Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...
removed the underpinning from that approach, with the claim that (at least according to the
Copenhagen interpretation) the most basic constituents of matter at times behave
indeterministically. This comes from the
collapse of the wave function, in which the state of a system upon
measurement
Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events.
In other words, measurement is a process of determining how large or small a physical quantity is as compared to ...
cannot in general be predicted. Quantum mechanics only predicts the probabilities of possible outcomes, which are given by the
Born rule. Non-deterministic behavior in wave function collapse is not only a feature of the Copenhagen interpretation, with its
observer-dependence, but also of
objective collapse and
other theories.
Opponents of quantum indeterminism suggested that determinism could be restored by formulating a new theory in which additional information, so-called
hidden variables, would allow definite outcomes to be determined. For instance, in 1935, Einstein, Podolsky and Rosen wrote a paper titled ''"
Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?"'' arguing that such a theory was in fact necessary to preserve the
principle of locality
In physics, the principle of locality states that an object is influenced directly only by its immediate surroundings. A theory that includes the principle of locality is said to be a "local theory". This is an alternative to the concept of ins ...
.
In 1964,
John S. Bell was able to define
a theoretical test for these local hidden variable theories, which was reformulated as a workable experimental test through the work of
Clauser, Horne, Shimony and Holt. The negative result of the 1980s
tests by
Alain Aspect ruled such theories out, provided certain
assumptions about the experiment hold. Thus any
interpretation of quantum mechanics, including deterministic reformulations, must either reject
locality or reject
counterfactual definiteness altogether.
David Bohm's
theory
A theory is a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, ...
is the main example of a non-local deterministic quantum theory.
The
many-worlds interpretation is said to be deterministic, but experimental results still cannot be predicted: experimenters do not know which 'world' they will end up in. Technically,
counterfactual definiteness is lacking.
A notable consequence of quantum indeterminism is the
Heisenberg uncertainty principle, which prevents the simultaneous accurate measurement of all a particle's properties.
Cosmology
Primordial fluctuations are density variations in the early universe which are considered the seeds of all
structure
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
in the universe. Currently, the most widely accepted explanation for their origin is in the context of
cosmic inflation. According to the inflationary paradigm, the exponential growth of the
scale factor during inflation caused
quantum fluctuations of the inflaton field to be stretched to macroscopic scales, and, upon leaving the
horizon
The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This curve divides all viewing directions based on whethe ...
, to "freeze in".
At the later stages of radiation- and matter-domination, these fluctuations re-entered the horizon, and thus set the
initial conditions for
structure formation.
Neuroscience
Neuroscientist
A neuroscientist (or neurobiologist) is a scientist specializing in neuroscience that deals with the anatomy and function of neurons, Biological neural network, neural circuits, and glia, and their Behavior, behavioral, biological, and psycholo ...
s such as
Björn Brembs and
Christof Koch believe thermodynamically
stochastic processes in the brain are the basis of
free will
Free will is generally understood as the capacity or ability of people to (a) choice, choose between different possible courses of Action (philosophy), action, (b) exercise control over their actions in a way that is necessary for moral respon ...
, and that even very simple organisms such as
flies
Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...
have a form of free will.
[BBC Science: ''Free Will Similar in Animals, Humans—But Not So Free''](_blank)
/ref> Similar ideas are put forward by some philosophers such as Robert Kane.
Despite recognizing indeterminism to be a very low-level, necessary prerequisite, Björn Brembs says that it's not even close to being sufficient for addressing things like morality and responsibility.
Other views
Against Einstein and others who advocated determinism
Determinism is the Metaphysics, metaphysical view that all events within the universe (or multiverse) can occur only in one possible way. Deterministic theories throughout the history of philosophy have developed from diverse and sometimes ov ...
, indeterminism—as championed by the English astronomer Sir Arthur Eddington—says that a physical object has an ontologically undetermined component that is not due to the epistemological
Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called "the theory of knowledge", it explores different types of knowledge, such as propositional knowledge about facts, practical knowled ...
limitations of physicists' understanding. The uncertainty principle
The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position a ...
, then, would not necessarily be due to hidden variables but to an indeterminism in nature itself.
Determinism and indeterminism are examined in ''Causality and Chance in Modern Physics'' by David Bohm. He speculates that, since determinism can emerge from underlying indeterminism (via the law of large numbers), and that indeterminism can emerge from determinism (for instance, from classical chaos), the universe could be conceived of as having alternating layers of causality and chaos.Bohm, D: ''Causality and Chance in Modern Physics'', pp. 29–33
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See also
* Catastrophism
* Chance (disambiguation)
* Interpretations of quantum mechanics: Comparisons chart
* Free will
Free will is generally understood as the capacity or ability of people to (a) choice, choose between different possible courses of Action (philosophy), action, (b) exercise control over their actions in a way that is necessary for moral respon ...
* Incompatibilism
Incompatibilism is the view that the thesis of determinism is logically incompatible with the classical thesis of free will. The term was coined in the 1960s, most likely by philosopher Keith Lehrer. The term ''compatibilism'' was coined (also by ...
* Luck
* Nondeterminism (disambiguation)
* Randomness
In common usage, randomness is the apparent or actual lack of definite pattern or predictability in information. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. ...
* Uncertainty
Uncertainty or incertitude refers to situations involving imperfect or unknown information. It applies to predictions of future events, to physical measurements that are already made, or to the unknown, and is particularly relevant for decision ...
References
Bibliography
* Lejeunne, Denis. 2012. ''The Radical Use of Chance in 20th Century Art'', Rodopi. Amsterdam
*James, William. The Dilemma of Determinism. Kessinger Publications, 2012.
*Narain, Vir, et al. “Determinism, Free Will, and Moral Responsibility.” TheHumanist.com, 21 Oct. 2014, thehumanist.com/magazine/november-december-2014/philosophically-speaking/determinism-free-will-and-moral-responsibility.
Russell, Bertrand. “Elements of Ethics.” Philosophical essays, 1910.
External links
Incompatibilist (Nondeterministic) Theories of Free Will
from the Stanford Encyclopedia of Philosophy
indeterminism
from the Philosophy Professor
Causal Determinism at the Stanford Encyclopedia of Philosophy
Norton, J.D. ''Causation as Folk Science''
{{Evolutionary psychology
Free will
Randomness
Determinism