5.1.1: Determinism

“Physical Determinism”³³

Physical determinism generally refers to the assertion of a deterministic physical universe (greater physical system). This holds that a complete description of the physical state of the world at any given time and a complete statement of the physical laws of nature together entail every truth as to what physical events happen after that time. In a scientific context, the term 'event' is somewhat technical, depending upon which theory one is considering, and basically is the occurrence of some 'state' peculiar to that theory, for example, a quantum state or a thermodynamic state. Physical determinism includes (but is not restricted to) nomological determinism, which holds that all future events are governed by the past or present according to all-encompassing deterministic laws.

The concept of physical determinism has also been used to denote the predictability of a physical system, although this usage is uncommon. Physical determinism can also be viewed as an observed phenomenon of our experience, or a thesis only relevant to mathematical models of physics and other physical sciences. Physical determinism has also been used as a specific deterministic hypothesis about human behavior. Although somewhat unrelated to its standard context, physical determinism has also been used in social engineering theory.

History

The notion of physical determinism takes its classical form in the ideas of Laplace, who posited (in agreement with the physics of his time) that an omniscient observer (called sometimes Laplace's demon) knowing with infinite precision the positions and velocities of every particle in the universe could predict the future entirely. Although such an omniscient observer is a hypothetical construct, and infinite precision exceeds the capacities of human measurement, the illustration is presented as a statement of what in principle would be possible if physical determinism were true, and so reduction to practice is not an issue.

Physical determinism is currently under heavy debate in modern science. For example, physical indeterminism has been proposed to accommodate various interpretations of quantum mechanics. Suggestions have also been made to reformulate the conception of determinism with respect to its application to physical law.

Causal completeness

Physical determinism is related to the question of causal completeness of physics, which is synonymous with the weaker form of causal closure. This is the idea that every real event has a scientific explanation, that science need not search for explanations beyond itself. If causal completeness does not apply to everything in the universe, then the door is open to events that are not subject to physical law. For example, a relatively common view of mental events is that they are an epiphenomenon produced as a by-product of neurological activity, and without causal impact. In this case, only a failure of deterministic physical law would allow room for their causal significance.

Other formulations

A more modern formulation of physical determinism skirts the issue of causal completeness. It is based upon connections between 'events' supplied by a theory:

"a theory is deterministic if, and only if, given its state variables for some initial period, the theory logically determines a unique set of values for those variables for any other period."

— Ernest Nagel, Alternative descriptions of physical state p. 292

This quote replaces the idea of 'cause-and-effect' with that of 'logical implication' according to one or another theory that connects events. In addition, an 'event' is related by the theory itself to formalized states described using the parameters defined by that theory. Thus, the details of interpretation are placed where they belong, fitted to the context in which the chosen theory applies. Using the definition of physical determinism above, the limitations of a theory to some particular domain of experience also limits the associated definition of 'physical determinism' to that same domain.

“Determinism”³⁴

Determinism is the philosophical position that for every event there exist conditions that could cause no other event. "There are many determinisms, depending on what pre-conditions are considered to be determinative of an event or action." Deterministic theories throughout the history of philosophy have sprung from diverse and sometimes overlapping motives and considerations. Some forms of determinism can be empirically tested with ideas from physics and the philosophy of physics. The opposite of determinism is some kind of indeterminism (otherwise called nondeterminism). Determinism is often contrasted with free will.

Determinism often is taken to mean causal determinism, which in physics is known as cause-and-effect. It is the concept that events within a given paradigm are bound by causality in such a way that any state (of an object or event) is completely determined by prior states. This meaning can be distinguished from other varieties of determinism mentioned below.

Other debates often concern the scope of determined systems, with some maintaining that the entire universe is a single determinate system and others identifying other more limited determinate systems (or multiverse). Numerous historical debates involve many philosophical positions and varieties of determinism. They include debates concerning determinism and free will, technically denoted as compatibilistic (allowing the two to coexist) and incompatibilistic (denying their coexistence is a possibility).

Determinism should not be confused with self-determination of human actions by reasons, motives, and desires. Determinism rarely requires that perfect prediction be practically possible.

Varieties

Below are some of the more common viewpoints meant by, or confused with "determinism".

• Causal determinism is "the idea that every event is necessitated by antecedent events and conditions together with the laws of nature". However, causal determinism is a broad enough term to consider that "one's deliberations, choices, and actions will often be necessary links in the causal chain that brings something about. In other words, even though our deliberations, choices, and actions are themselves determined like everything else, it is still the case, according to causal determinism, that the occurrence or existence of yet other things depends upon our deliberating, choosing and acting in a certain way". Causal determinism proposes that there is an unbroken chain of prior occurrences stretching back to the origin of the universe. The relation between events may not be specified, nor the origin of that universe. Causal determinists believe that there is nothing in the universe that is uncaused or self-caused. Historical determinism (a sort of path dependence) can also be synonymous with causal determinism. Causal determinism has also been considered more generally as the idea that everything that happens or exists is caused by antecedent conditions. In the case of nomological determinism, these conditions are considered events also, implying that the future is determined completely by preceding events—a combination of prior states of the universe and the laws of nature. Yet they can also be considered metaphysical of origin (such as in the case of theological determinism).
• Nomological determinism is the most common form of causal determinism. It is the notion that the past and the present dictate the future entirely and necessarily by rigid natural laws, that every occurrence results inevitably from prior events. Quantum mechanics and various interpretations thereof pose a serious challenge to this view. Nomological determinism is sometimes illustrated by the thought experiment of Laplace's demon. Nomological determinism is sometimes called 'scientific' determinism, although that is a misnomer. Physical determinism is generally used synonymously with nomological determinism (its opposite being physical indeterminism).
• Necessitarianism is closely related to the causal determinism described above. It is a metaphysical principle that denies all mere possibility; there is exactly one way for the world to be. Leucippus claimed there were no uncaused events, and that everything occurs for a reason and by necessity.
• Predeterminism is the idea that all events are determined in advance. The concept of predeterminism is often argued by invoking causal determinism, implying that there is an unbroken chain of prior occurrences stretching back to the origin of the universe. In the case of predeterminism, this chain of events has been pre-established, and human actions cannot interfere with the outcomes of this pre-established chain. Predeterminism can be used to mean such pre-established causal determinism, in which case it is categorised as a specific type of determinism. It can also be used interchangeably with causal determinism—in the context of its capacity to determine future events. Despite this, predeterminism is often considered as independent of causal determinism. The term predeterminism is also frequently used in the context of biology and hereditary, in which case it represents a form of biological determinism.
• Fatalism is normally distinguished from "determinism" and it is a form of teleological determinism. Fatalism is the idea that everything is fated to happen, so that humans have no control over their future. Fate has arbitrary power, and need not follow any causal or otherwise deterministic laws. Types of Fatalism include hard theological determinism and the idea of predestination, where there is a God who determines all that humans will do. This may be accomplished either by knowing their actions in advance, via some form of omniscience or by decreeing their actions in advance.
• Theological determinism is a form of determinism which states that all events that happen are pre-ordained, or predestined to happen, by a monotheistic deity, or that they are destined to occur given its omniscience. Two forms of theological determinism exist, here referenced as strong and weak theological determinism. The first one, strong theological determinism, is based on the concept of a creator deity dictating all events in history: "everything that happens has been predestined to happen by an omniscient, omnipotent divinity". The second form, weak theological determinism, is based on the concept of divine foreknowledge—"because God's omniscience is perfect, what God knows about the future will inevitably happen, which means, consequently, that the future is already fixed". There exist slight variations on the above categorisation. Some claim that theological determinism requires predestination of all events and outcomes by the divinity (i.e. they do not classify the weaker version as 'theological determinism' unless libertarian free will is assumed to be denied as a consequence), or that the weaker version does not constitute 'theological determinism' at all. With respect to free will, "theological determinism is the thesis that God exists and has infallible knowledge of all true propositions including propositions about our future actions", more minimal criteria designed to encapsulate all forms of theological determinism. Theological determinism can also be seen as a form of causal determinism, in which the antecedent conditions are the nature and will of God.
• Logical determinism or Determinateness is the notion that all propositions, whether about the past, present, or future, are either true or false. Note that one can support Causal Determinism without necessarily supporting Logical Determinism and vice versa (depending on one's views on the nature of time, but also randomness). The problem of free will is especially salient now with Logical Determinism: how can choices be free, given that propositions about the future already have a truth value in the present (i.e. it is already determined as either true or false)? This is referred to as the problem of future contingents.
• Often synonymous with Logical Determinism are the ideas behind Spatio-temporal Determinism or Eternalism: the view of special relativity. J. J. C. Smart, a proponent of this view, uses the term "tenselessness" to describe the simultaneous existence of past, present, and future. In physics, the "block universe" of Hermann Minkowski and Albert Einstein assumes that time is a fourth dimension (like the three spatial dimensions). In other words, all the other parts of time are real, like the city blocks up and down a street, although the order in which they appear depends on the driver (see Rietdijk–Putnam argument).
• Adequate determinism is the idea that quantum indeterminacy can be ignored for most macroscopic events. This is because of quantum decoherence. Random quantum events "average out" in the limit of large numbers of particles (where the laws of quantum mechanics asymptotically approach the laws of classical mechanics). Stephen Hawking explains a similar idea: he says that the microscopic world of quantum mechanics is one of determined probabilities. That is, quantum effects rarely alter the predictions of classical mechanics, which are quite accurate (albeit still not perfectly certain) at larger scales. Something as large as an animal cell, then, would be "adequately determined" (even in light of quantum indeterminacy).
• The Many-worlds interpretation accepts the linear casual sets of sequential events with adequate consistency yet also suggests constant forking of casual chains creating "multiple universes" to account for multiple outcomes from single events. Meaning the casual set of events leading to the present are all valid yet appear as a singular linear time stream within a much broader unseen conic probability field of other outcomes that "split off" from the locally observed timeline. Under this model causal sets are still "consistent" yet not exclusive to singular iterated outcomes. The interpretation side steps the exclusive retrospective casual chain problem of "could not have done otherwise" by suggesting "the other outcome does exist" in a set of parallel universe time streams that split off when the action occurred. This theory is sometimes described with the example of agent based choices but more involved models argue that recursive causal splitting occurs with all particle wave functions at play. This model is highly contested with multiple objections from the scientific community.

Philosophical connections

With nature/nurture controversy

Although some of the above forms of determinism concern human behaviors and cognition, others frame themselves as an answer to the debate on nature and nurture. They will suggest that one factor will entirely determine behavior. As scientific understanding has grown, however, the strongest versions of these theories have been widely rejected as a single-cause fallacy.

In other words, the modern deterministic theories attempt to explain how the interaction of both nature and nurture is entirely predictable. The concept of heritability has been helpful in making this distinction.

Biological determinism, sometimes called genetic determinism, is the idea that each of human behaviors, beliefs, and desires are fixed by human genetic nature.

Behaviorism involves the idea that all behavior can be traced to specific causes—either environmental or reflexive. John B. Watson and B. F. Skinner developed this nurture-focused determinism.

Cultural determinism or social determinism is the nurture-focused theory that the culture in which we are raised determines who we are.

Environmental determinism, also known as climatic or geographical determinism, proposes that the physical environment, rather than social conditions, determines culture. Supporters of environmental determinism often also support Behavioral determinism. Key proponents of this notion have included Ellen Churchill Semple, Ellsworth Huntington, Thomas Griffith Taylor and possibly Jared Diamond, although his status as an environmental determinist is debated.

With particular factors

Other 'deterministic' theories actually seek only to highlight the importance of a particular factor in predicting the future. These theories often use the factor as a sort of guide or constraint on the future. They need not suppose that complete knowledge of that one factor would allow us to make perfect predictions.

Psychological determinism can mean that humans must act according to reason, but it can also be synonymous with some sort of Psychological egoism. The latter is the view that humans will always act according to their perceived best interest.

Linguistic determinism claims that our language determines (at least limits) the things we can think and say and thus know. The Sapir–Whorf hypothesis argues that individuals experience the world based on the grammatical structures they habitually use.

Economic determinism is the theory which attributes primacy to the economic structure over politics in the development of human history. It is associated with the dialectical materialism of Karl Marx.

Technological determinism is a reductionist theory that presumes that a society's technology drives the development of its social structure and cultural values.

With free will

Philosophers have debated both the truth of determinism, and the truth of free will. Compatibilism refers to the view that free will is, in some sense, compatible with determinism. The three incompatibilist positions, on the other hand, deny this possibility. The hard incompatibilists hold that both determinism and free will do not exist, the libertarianists that determinism does not hold, and free will might exist, and the hard determinists that determinism does hold and free will does not exist.

The standard argument against free will, according to philosopher J. J. C. Smart focuses on the implications of determinism for 'free will'. However, he suggests free will is denied whether determinism is true or not. On one hand, if determinism is true, all our actions are predicted and we are assumed not to be free; on the other hand, if determinism is false, our actions are presumed to be random and as such we do not seem free because we had no part in controlling what happened.

In his book, The Moral Landscape, author and neuroscientist Sam Harris also argues against free will. He offers one thought experiment where a mad scientist represents determinism. In Harris' example, the mad scientist uses a machine to control all the desires, and thus all the behavior, of a particular human. Harris believes that it is no longer as tempting, in this case, to say the victim has "free will". Harris says nothing changes if the machine controls desires at random - the victim still seems to lack free will.

Harris then argues that we are also the victims of such unpredictable desires (but due to the unconscious machinations of our brain, rather than those of a mad scientist). Based on this introspection, he writes "This discloses the real mystery of free will: if our experience is compatible with its utter absence, how can we say that we see any evidence for it in the first place?" adding that "Whether they are predictable or not, we do not cause our causes." That is, he believes there is compelling evidence of absence of free will.

Some research (founded by the John Templeton Foundation) suggested that reducing a person's belief in free will is dangerous, making them less helpful and more aggressive. This could occur because the individual's sense of self-efficacy suffers.

With the soul

Some determinists argue that materialism does not present a complete understanding of the universe, because while it can describe determinate interactions among material things, it ignores the minds or souls of conscious beings.

A number of positions can be delineated:

1. Immaterial souls are all that exist (Idealism).
2. Immaterial souls exist and exert a non-deterministic causal influence on bodies. (Traditional free-will, interactionist dualism).
3. Immaterial souls exist, but are part of deterministic framework.
4. Immaterial souls exist, but exert no causal influence, free or determined (epiphenomenalism, occasionalism)
5. Immaterial souls do not exist — there is no mind-body dichotomy, and there is a Materialistic explanation for intuitions to the contrary.

With ethics and morality

Another topic of debate is the implication that Determinism has on morality. Hard determinism (a belief in determinism, and not free will) is particularly criticized for seeming to make traditional moral judgments impossible. Some philosophers, however, find this an acceptable conclusion.

Philosopher and incompatibilist Peter van Inwagen introduces this thesis as such:

Argument that Free Will is Required for Moral Judgments

1. The moral judgment that you shouldn't have done X implies that you should have done something else instead
2. That you should have done something else instead implies that there was something else for you to do
3. That there was something else for you to do implies that you could have done something else
4. That you could have done something else implies that you have free will
5. If you don't have free will to have done other than X we cannot make the moral judgment that you shouldn't have done X.

However, a compatibilist might have an issue with Inwagen's process because one can not change the past like his arguments center around. A compatibilist who centers around plans for the future might posit:

1. The moral judgment that you should not have done X implies that you can do something else instead
2. That you can do something else instead implies that there is something else for you to do
3. That there is something else for you to do implies that you can do something else
4. That you can do something else implies that you have free will for planning future recourse
5. If you have free will to do other than X we can make the moral judgment that you should do other than X, and punishing you as a responsible party for having done X that you know you should not have done can help you remember to not do X in the future.