A 'deterministic system' is a conceptual model of the
philosophical doctrine of
determinism applied to a
system for understanding everything that has and will occur in the system, based on the physical outcomes of
causality. In a deterministic system, every action, or cause, produces a reaction, or effect, and every reaction, in turn, becomes the cause of subsequent reactions. The totality of these cascading events can theoretically show exactly how the system will exist at any moment in
time.
An example system
To understand this concept, start with a fairly small everyday system. Visualize a set of three
dominoes lined up in a row with each domino less than a domino's length away from its neighbors, impervious to
external environment influences. Once the first domino has toppled, the third domino will topple because the second will topple upon being contacted by the first domino. This could feasibly be shown by a
scientist using a
computer model front-loaded with the ability to correctly apply physics.
Small deterministic systems are easy to visualize, but are necessarily linked to the rest of reality by an initial cause and/or final effect. To go back to the dominoes, something outside the system has to cause the first domino to topple. The last domino falling might cause something else outside the system to happen. And the system itself must be considered in isolation--if external forces such as hurricanes, earthquakes or the hands of nearby people were taken into consideration, the final domino toppling might not be a predetermined outcome. Complete isolation of a system is unrealistic, but useful for understanding what would normally happen to a system when the possibility of external influences is negligible. Complex physical systems are necessarily built using simpler ones, and using isolated systems as a starting model can help bridge the gap and aid in understanding. The domino example is developed in the
Petri net computational model.
This example assumes that dominoes toppling into each other behave deterministically. Even the above-mentioned external forces which might interrupt the system are causes which the system did not consider, but which could be explained by cause and effect in a larger deterministic system.
Or otherwise stated : A system in which the later states of the system follow from, or are determined by, the earlier ones. Such a system contrasts with a stochastic or random system in which future states are not determined from previous ones. An example of a stochastic system would be the sequence of heads or tails of an unbiased coin, or radioactive decay.
If a system is deterministic, this doesn’t necessarily imply that later states of the system are predictable from a knowledge of the earlier ones. In this way, chaos is similar to a random system. For example, chaos has been termed "deterministic chaos" since, although it is determined by simple rules, its property of sensitive dependence on initial conditions makes a chaotic system, in practice, largely unpredictable.
Some deterministic systems
★
Classical physics is the deterministic system assumed in the domino example which scientists can use to describe all events which take place on a scale larger than individual atoms. Classical physics includes
Newton's laws of motion,
Classical electrodynamics,
thermodynamics, the
Special theory of relativity, the
General theory of relativity,
chaos theory and
nonlinear dynamics. Some of these systems are complex, and events may be difficult to predict in practice, but if the starting conditions were known in enough detail, the outcomes of events in such systems could be predicted.
★ Nearly all electronic
computers in use today are based on theoretical
von Neumann computers or
Turing machines, i.e.: they are devices that perform one small, deterministic step at a time. If all inputs are specified, the computer will always produce a particular output which is calculated deterministically. Computer scientists also study other models of computation including
parallel computers (more than one deterministic step at a time), and
quantum computers (which are based on non-deterministic quantum mechanical models).
★ Some schools of
Islamic thought dictate that the world is predetermined in
Hadith. "If the whole community gathered to help you, they could only help you with what God has already prescribed for you. If the whole community gathered to harm you, they could only harm you with what God has already prescribed for you. The pens have been lifted, the pages, dried." Other schools of Islamic thought describe a less restricted view, indeed the Quran itself describes the actions of people to undetermined and that actions proceed from volition conveyed through the agency of the soul.
★
Behaviorism, an approach to psychology based on the proposition that behavior can be researched scientifically without recourse to inner mental states, is usually considered to be deterministic and opposed to free will.
Some non-deterministic systems
Events without natural causes could not be part of a deterministic system. Whether such events actually occur is a matter of philosophical and scientific debate, but possible uncaused events include:
★ Completely random events
:
Quantum physics holds that certain events such as
radioactive decay and
movement of particles are completely random when taken at the level of single atoms or smaller.
Schrödinger's cat is a famous
thought experiment in which a cat's survival cannot be determined theoretically before the experiment is done. For almost all everyday non-microscopic occurrences, however, the probability of such random events is extremely close to zero, and can be approximated to almost certainty with statistics using the
correspondence principle. The philosophical consequences of quantum physics were once considered by many (including
Albert Einstein) to be a major problem for the scientific method which traditionally used a strong version of
scientific determinism (see
Philosophy of science).
★ Mysterious miracles
:A
miracle such as the
resurrection of Jesus (as believed by Christians) is considered as such because the effect is mysterious and has no natural cause--supernatural causes cannot be part of a deterministic system.
Systems with controversial classification
Some systems are particularly difficult to classify as deterministic or not, and have generated much philosophical debate. The major example would be human minds, and possibly animal minds too. Can people have
free will if their minds are truly deterministic? Conversely, when deterministic computers are said to exhibit
artificial intelligence, how are their minds similar to ours?
The entire universe
The larger the deterministic system, the longer the necessary chain of cause and effect. The entire
universe may be considered as such a system, which creates its own philosophical questions (see
Determinism).
See also
★
Chaos theory
★
Classical mechanics
★
Classical physics
★
Determinism
★
Deterministic system (mathematics)
★
Free Will
★
Philosophy of science
★
Quantum indeterminacy
★
Quantum mechanics
★
Quantum mind
★
Scientific determinism
★
Uncertainty principle
★
Indeterminacy