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Since the beginning of the 20th century, [[quantum mechanics]] has revealed previously concealed aspects of events. Newtonian physics, taken in [[isolation]] rather than as an approximation to quantum mechanics, depicts a [[universe]] in which objects move in perfectly determinative ways. At human scale levels of interaction, Newtonian mechanics makes predictions that are agreed with, within the accuracy of measurement. Poorly designed and fabricated guns and ammunition scatter their shots rather widely around the center of a target, and better guns produce tighter [[pattern]]s. [[Absolute]] [[knowledge]] of the [[force]]s accelerating a bullet should produce absolutely reliable predictions of its path, or so was thought. However, knowledge is never absolute in [[practice]] and the [[equation]]s of Newtonian mechanics can exhibit sensitive dependence on initial conditions, meaning small errors in knowledge of initial conditions can result in arbitrarily large deviations from predicted behavior.

Since the beginning of the 20th century, [[quantum mechanics]] has revealed previously concealed aspects of events. Newtonian physics, taken in [[isolation]] rather than as an approximation to quantum mechanics, depicts a [[universe]] in which objects move in perfectly determinative ways. At human scale levels of interaction, Newtonian mechanics makes predictions that are agreed with, within the accuracy of measurement. Poorly designed and fabricated guns and ammunition scatter their shots rather widely around the center of a target, and better guns produce tighter [[pattern]]s. [[Absolute]] [[knowledge]] of the [[force]]s accelerating a bullet should produce absolutely reliable predictions of its path, or so was thought. However, knowledge is never absolute in [[practice]] and the [[equation]]s of Newtonian mechanics can exhibit sensitive dependence on initial conditions, meaning small errors in knowledge of initial conditions can result in arbitrarily large deviations from predicted behavior.

At atomic scales the paths of objects can only be predicted in a [[probabilistic]] way. The paths may not be exactly specified in a full quantum description of the particles; "path" is a classical concept which quantum particles do not exactly possess. The probability arises from the measurement of the perceived path of the particle. In some cases, a [[quantum particle]] may trace an exact path, and the probability of finding the particles in that path is one. The quantum development is at least as predictable as the classical motion, but it describes wave functions that cannot be easily expressed in ordinary [[language]]. In double-slit experiments, [[photons]] are fired singly through a double-slit apparatus at a distant screen and do not arrive at a single point, nor do the photons arrive in a scattered pattern [[analogous]] to bullets fired by a fixed gun at a distant target. Instead, the [[light]] arrives in varying concentrations at widely separated points, and the distribution of its collisions with the target can be calculated reliably. In that sense the behavior of light in this apparatus is deterministic, but there is no way to predict where in the resulting interference pattern an individual photon will make its contribution (see [http://en.wikipedia.org/wiki/Heisenberg_Uncertainty_Principle Heisenberg Uncertainty Principle]).

At atomic scales the paths of objects can only be predicted in a [[probabilistic]] way. The paths may not be exactly specified in a full quantum description of the particles; "path" is a classical concept which quantum particles do not exactly possess. The probability arises from the measurement of the perceived path of the particle. In some cases, a [[quantum particle]] may trace an exact path, and the probability of finding the particles in that path is one. The quantum development is at least as predictable as the classical motion, but it describes wave functions that cannot be easily expressed in ordinary [[language]]. In double-slit experiments, [[photons]] are fired singly through a double-slit apparatus at a distant screen and do not arrive at a single point, nor do the photons arrive in a scattered pattern [[analogous]] to bullets fired by a fixed gun at a distant target. Instead, the [[light]] arrives in varying concentrations at widely separated points, and the distribution of its collisions with the target can be calculated reliably. In that sense the behavior of light in this apparatus is deterministic, but there is no way to predict where in the resulting interference pattern an individual photon will make its contribution (see [https://en.wikipedia.org/wiki/Heisenberg_Uncertainty_Principle Heisenberg Uncertainty Principle]).

Some have argued that, in addition to the [[human condition|conditions humans]] can observe and the laws we can deduce, there are hidden factors or "hidden variables" that determine absolutely in which order photons reach the detector screen. They argue that the course of the universe is absolutely determined, but that humans are screened from [[knowledge]] of the determinative factors. So, they say, it only appears that things proceed in a merely probabilistically-determinative way. In [[actuality]], they proceed in an absolutely deterministic way. Although matters are still subject to some measure of dispute, quantum mechanics makes statistical [[prediction]]s which would be violated if some local hidden variables existed. There have been a number of [[experiment]]s to verify those predictions, and so far they do not appear to be violated, though many physicists believe better experiments are needed to conclusively settle the question. (See [http://en.wikipedia.org/wiki/Bell_test_experiments Bell test experiments].) It is possible, however, to augment quantum mechanics with non-local hidden variables to achieve a deterministic theory that is in agreement with experiment. An example is the [http://en.wikipedia.org/wiki/Bohm_interpretation Bohm interpretation] of quantum mechanics.

Some have argued that, in addition to the [[human condition|conditions humans]] can observe and the laws we can deduce, there are hidden factors or "hidden variables" that determine absolutely in which order photons reach the detector screen. They argue that the course of the universe is absolutely determined, but that humans are screened from [[knowledge]] of the determinative factors. So, they say, it only appears that things proceed in a merely probabilistically-determinative way. In [[actuality]], they proceed in an absolutely deterministic way. Although matters are still subject to some measure of dispute, quantum mechanics makes statistical [[prediction]]s which would be violated if some local hidden variables existed. There have been a number of [[experiment]]s to verify those predictions, and so far they do not appear to be violated, though many physicists believe better experiments are needed to conclusively settle the question. (See [https://en.wikipedia.org/wiki/Bell_test_experiments Bell test experiments].) It is possible, however, to augment quantum mechanics with non-local hidden variables to achieve a deterministic theory that is in agreement with experiment. An example is the [https://en.wikipedia.org/wiki/Bohm_interpretation Bohm interpretation] of quantum mechanics.

On the macro scale it can matter very much whether a bullet arrives at a certain point at a certain time, as snipers are well aware; there are analogous quantum events that have macro- as well as quantum-level consequences. It is easy to contrive situations in which the arrival of an [[electron]] at a screen at a certain point and [[time]] would trigger one event and its arrival at another point would trigger an entirely different event. (See [http://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat Schrödinger's cat].)

On the macro scale it can matter very much whether a bullet arrives at a certain point at a certain time, as snipers are well aware; there are analogous quantum events that have macro- as well as quantum-level consequences. It is easy to contrive situations in which the arrival of an [[electron]] at a screen at a certain point and [[time]] would trigger one event and its arrival at another point would trigger an entirely different event. (See [https://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat Schrödinger's cat].)

Even before the laws of quantum mechanics were fully developed, the [[phenomenon]] of [[radioactivity]] posed a challenge to determinism. A gram of [http://en.wikipedia.org/wiki/Uranium-238 uranium-238], a commonly occurring radioactive substance, contains some 2.5 x 1021 [[atoms]]. By all tests known to [[science]] these atoms are identical and indistinguishable. Yet about 12600 times a second one of the atoms in that gram will decay, giving off an alpha particle. This decay does not depend on external stimulus and no extant [[theory]] of [[physics]] predicts when any given atom will decay, with realistically obtainable knowledge. The uranium found on [[earth]] is thought to have been synthesized during a [[supernova]] that occurred roughly 5 billion years ago. For determinism to hold, every uranium atom must contain some internal "clock" that specifies the exact time it will decay.[citation needed] And somehow the laws of physics must specify exactly how those clocks were set as each uranium atom was formed during the supernova collapse.

Even before the laws of quantum mechanics were fully developed, the [[phenomenon]] of [[radioactivity]] posed a challenge to determinism. A gram of [https://en.wikipedia.org/wiki/Uranium-238 uranium-238], a commonly occurring radioactive substance, contains some 2.5 x 1021 [[atoms]]. By all tests known to [[science]] these atoms are identical and indistinguishable. Yet about 12600 times a second one of the atoms in that gram will decay, giving off an alpha particle. This decay does not depend on external stimulus and no extant [[theory]] of [[physics]] predicts when any given atom will decay, with realistically obtainable knowledge. The uranium found on [[earth]] is thought to have been synthesized during a [[supernova]] that occurred roughly 5 billion years ago. For determinism to hold, every uranium atom must contain some internal "clock" that specifies the exact time it will decay.[citation needed] And somehow the laws of physics must specify exactly how those clocks were set as each uranium atom was formed during the supernova collapse.

Exposure to alpha radiation can cause [[cancer]]. For this to happen, at some point a specific alpha particle must alter some chemical reaction in a cell in a way that results in a mutation. Since molecules are in constant thermal [[motion]], the exact timing of the radioactive decay that produced the fatal alpha particle matters. If probabilistically determined events do have an impact on the macro events—such as when a person who could have been historically important dies in youth of a cancer caused by a random mutation—then the course of history is not predictable from the dawn of time.

Exposure to alpha radiation can cause [[cancer]]. For this to happen, at some point a specific alpha particle must alter some chemical reaction in a cell in a way that results in a mutation. Since molecules are in constant thermal [[motion]], the exact timing of the radioactive decay that produced the fatal alpha particle matters. If probabilistically determined events do have an impact on the macro events—such as when a person who could have been historically important dies in youth of a cancer caused by a random mutation—then the course of history is not predictable from the dawn of time.

The time dependent [http://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation Schrödinger equation] gives the first time derivative of the [http://en.wikipedia.org/wiki/Quantum_state quantum state]. That is, it explicitly and [[unique]]ly predicts the development of the wave function with time.

The time dependent [https://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation Schrödinger equation] gives the first time derivative of the [https://en.wikipedia.org/wiki/Quantum_state quantum state]. That is, it explicitly and [[unique]]ly predicts the development of the wave function with time.

[[File:Schrodinger_equation_2.jpg]]

[[File:Schrodinger_equation_2.jpg]]

So quantum mechanics is deterministic, provided that one accepts the [[wave]] function itself as [[reality]] (rather than as probability of classical coordinates). Since we have no practical way of knowing the exact magnitudes, and especially the [[phase]]s, in a full quantum mechanical description of the causes of an observable event, this turns out to be philosophically similar to the "hidden variable" doctrine.

So quantum mechanics is deterministic, provided that one accepts the [[wave]] function itself as [[reality]] (rather than as probability of classical coordinates). Since we have no practical way of knowing the exact magnitudes, and especially the [[phase]]s, in a full quantum mechanical description of the causes of an observable event, this turns out to be philosophically similar to the "hidden variable" doctrine.

According to some, quantum mechanics is more strongly ordered than Classical Mechanics, because while Classical Mechanics is [[chaos|chaotic]], quantum mechanics is not. For example, the classical problem of three bodies under a [[force]] such as [[gravity]] is not integrable, while the quantum mechanical three body problem is tractable and integrable, using the [http://en.wikipedia.org/wiki/Faddeev_Equations Faddeev Equations]. That is, the quantum mechanical problem can always be solved to a given accuracy with a large enough computer of predetermined precision, while the classical problem may require [[arbitrary|arbitrarily]] high precision, depending on the details of the [[motion]]. This does not mean that quantum mechanics describes the world as more deterministic, unless one already considers the wave function to be the true reality. Even so, this does not get rid of the probabilities, because we can't do anything without using classical descriptions, but it assigns the probabilities to the classical approximation, rather than to the quantum reality.

According to some, quantum mechanics is more strongly ordered than Classical Mechanics, because while Classical Mechanics is [[chaos|chaotic]], quantum mechanics is not. For example, the classical problem of three bodies under a [[force]] such as [[gravity]] is not integrable, while the quantum mechanical three body problem is tractable and integrable, using the [https://en.wikipedia.org/wiki/Faddeev_Equations Faddeev Equations]. That is, the quantum mechanical problem can always be solved to a given accuracy with a large enough computer of predetermined precision, while the classical problem may require [[arbitrary|arbitrarily]] high precision, depending on the details of the [[motion]]. This does not mean that quantum mechanics describes the world as more deterministic, unless one already considers the wave function to be the true reality. Even so, this does not get rid of the probabilities, because we can't do anything without using classical descriptions, but it assigns the probabilities to the classical approximation, rather than to the quantum reality.

Asserting that quantum mechanics is deterministic by treating the wave function itself as reality implies a single [[wave]] function for the entire [[universe]], starting at the [[origin]] of the [[universe]]. Such a "wave function of everything" would carry the probabilities of not just the world we know, but every other possible world that could have evolved. For example, large voids in the distributions of galaxies are believed by many [[cosmology|cosmologists]] to have originated in quantum fluctuations during the big bang. (See [http://en.wikipedia.org/wiki/Cosmic_inflation cosmic inflation] and [http://en.wikipedia.org/wiki/Primordial_fluctuations primordial fluctuations].) If so, the "wave function of everything" would carry the possibility that the region where our [[Milky Way]] galaxy is located could have been a void and the Earth never existed at all. (See large-scale structure of the cosmos.)

Asserting that quantum mechanics is deterministic by treating the wave function itself as reality implies a single [[wave]] function for the entire [[universe]], starting at the [[origin]] of the [[universe]]. Such a "wave function of everything" would carry the probabilities of not just the world we know, but every other possible world that could have evolved. For example, large voids in the distributions of galaxies are believed by many [[cosmology|cosmologists]] to have originated in quantum fluctuations during the big bang. (See [https://en.wikipedia.org/wiki/Cosmic_inflation cosmic inflation] and [https://en.wikipedia.org/wiki/Primordial_fluctuations primordial fluctuations].) If so, the "wave function of everything" would carry the possibility that the region where our [[Milky Way]] galaxy is located could have been a void and the Earth never existed at all. (See large-scale structure of the cosmos.)

==First cause==

==First cause==

Intrinsic to the debate concerning determinism is the issue of first cause. [[Deism]], a philosophy articulated in the seventeenth century, holds that the universe has been deterministic since [[creation]], but ascribes the creation to a [[metaphysical]] God or first cause outside of the chain of determinism. God may have begun the [[process]], Deism argues, but God has not influenced its [[evolution]]. This [[perspective]] illustrates a puzzle underlying any conception of determinism:

Intrinsic to the debate concerning determinism is the issue of first cause. [[Deism]], a philosophy articulated in the seventeenth century, holds that the universe has been deterministic since [[creation]], but ascribes the creation to a [[metaphysical]] God or first cause outside of the chain of determinism. God may have begun the [[process]], Deism argues, but God has not influenced its [[evolution]]. This [[perspective]] illustrates a puzzle underlying any conception of determinism:

# Fischer, John Martin (1989) God, Foreknowledge and Freedom. Stanford, CA: Stanford University Press. ISBN 1-55786-857-3

# Fischer, John Martin (1989) God, Foreknowledge and Freedom. Stanford, CA: Stanford University Press. ISBN 1-55786-857-3

# Watt, Montgomery (1948) Free-Will and Predestination in Early Islam. London:Luzac & Co.

# Watt, Montgomery (1948) Free-Will and Predestination in Early Islam. London:Luzac & Co.

# Swartz, Norman (2003) The Concept of Physical Law / Chapter 10: Free Will and Determinism ( http://www.sfu.ca/philosophy/physical-law/)

# Swartz, Norman (2003) The Concept of Physical Law / Chapter 10: Free Will and Determinism ( https://www.sfu.ca/philosophy/physical-law/)

# By 'soul' in the context of (1) is meant an autonomous immaterial agent that has the power to control the body but not to be controlled by the body (this theory of determinism thus conceives of conscious agents in dualistic terms). Therefore the soul stands to the activities of the individual agent's body as does the creator of the universe to the universe. The creator of the universe put in motion a deterministic system of material entities that would, if left to themselves, carry out the chain of events determined by ordinary causation. But the creator also provided for souls that could exert a causal force analogous to the primordial causal force and alter outcomes in the physical universe via the acts of their bodies. Thus, it emerges that no events in the physical universe are uncaused. Some are caused entirely by the original creative act and the way it plays itself out through time, and some are caused by the acts of created souls. But those created souls were not created by means of physical processes involving ordinary causation. They are another order of being entirely, gifted with the power to modify the original creation. However, determinism is not necessarily limited to matter; it can encompass energy as well. The question of how these immaterial entities can act upon material entities is deeply involved in what is generally known as the mind-body problem. It is a significant problem which philosophers have not reached agreement about

# By 'soul' in the context of (1) is meant an autonomous immaterial agent that has the power to control the body but not to be controlled by the body (this theory of determinism thus conceives of conscious agents in dualistic terms). Therefore the soul stands to the activities of the individual agent's body as does the creator of the universe to the universe. The creator of the universe put in motion a deterministic system of material entities that would, if left to themselves, carry out the chain of events determined by ordinary causation. But the creator also provided for souls that could exert a causal force analogous to the primordial causal force and alter outcomes in the physical universe via the acts of their bodies. Thus, it emerges that no events in the physical universe are uncaused. Some are caused entirely by the original creative act and the way it plays itself out through time, and some are caused by the acts of created souls. But those created souls were not created by means of physical processes involving ordinary causation. They are another order of being entirely, gifted with the power to modify the original creation. However, determinism is not necessarily limited to matter; it can encompass energy as well. The question of how these immaterial entities can act upon material entities is deeply involved in what is generally known as the mind-body problem. It is a significant problem which philosophers have not reached agreement about

# Free Will (Stanford Encyclopedia of Philosophy)

# Free Will (Stanford Encyclopedia of Philosophy)

==References and bibliography==

==References and bibliography==

*Albert Messiah, Quantum Mechanics, English translation by G. M. Temmer of Mécanique Quantique, 1966, John Wiley and Sons, vol. I, chapter IV, section III.

*Albert Messiah, Quantum Mechanics, English translation by G. M. Temmer of Mécanique Quantique, 1966, John Wiley and Sons, vol. I, chapter IV, section III.

*A lecture to his statistical mechanics class at the University of California at Santa Barbara by Dr. Herbert P. Broida [http://sunsite.berkeley.edu/uchistory/archives_exhibits/in_memoriam/catalog/broida_herbert.html 4] (1920–1978) (a well known experimental physicist)

*A lecture to his statistical mechanics class at the University of California at Santa Barbara by Dr. Herbert P. Broida [https://sunsite.berkeley.edu/uchistory/archives_exhibits/in_memoriam/catalog/broida_herbert.html 4] (1920–1978) (a well known experimental physicist)

*Dennett D. (2003) Freedom Evolves. Viking Penguin, NY, USA.

*Dennett D. (2003) Freedom Evolves. Viking Penguin, NY, USA.

*"Physics and the Real World" by George F. R. Ellis, Physics Today, July, 2005

*"Physics and the Real World" by George F. R. Ellis, Physics Today, July, 2005

== External links ==

== External links ==

* [http://robomaker.bplaced.net/?p=3 Can you show me the way to the human soul? Thanks!]

* [https://robomaker.bplaced.net/?p=3 Can you show me the way to the human soul? Thanks!]

* [http://plato.stanford.edu/entries/determinism-causal/ Stanford Encyclopedia of Philosophy entry on Causal Determinism]

* [https://plato.stanford.edu/entries/determinism-causal/ Stanford Encyclopedia of Philosophy entry on Causal Determinism]

* [http://etext.lib.virginia.edu/cgi-local/DHI/dhi.cgi?id=dv2-02 Determinism in History] from the ''Dictionary of the History of Ideas''

* [https://etext.lib.virginia.edu/cgi-local/DHI/dhi.cgi?id=dv2-02 Determinism in History] from the ''Dictionary of the History of Ideas''

* [http://www.ucl.ac.uk/~uctytho/dfwIntroIndex.htm Philosopher Ted Honderich's Determinism web resource]

* [https://www.ucl.ac.uk/~uctytho/dfwIntroIndex.htm Philosopher Ted Honderich's Determinism web resource]

* [http://www.galilean-library.org/int13.html An Introduction to Free Will and Determinism] by Paul Newall, aimed at beginners.

* [https://www.galilean-library.org/int13.html An Introduction to Free Will and Determinism] by Paul Newall, aimed at beginners.

* [http://www.determinism.com The Society of Natural Science]

* [https://www.determinism.com The Society of Natural Science]

* [http://www.chabad.org/article.asp?AID=3017 Determinism and Free Will in Judaism]

* [https://www.chabad.org/article.asp?AID=3017 Determinism and Free Will in Judaism]

* [http://www.jottings.ca/john/cogitations.html Snooker, Pool, and Determinism]

* [https://www.jottings.ca/john/cogitations.html Snooker, Pool, and Determinism]

[[Category: Philosophy]]

[[Category: Philosophy]]