What is determinism

Philosophy understandable


The term "determinism" is used in many different contexts. One speaks of, among other things logical Determinism, of theological Determinism and from causal (or physical) Determinism. [Note: The term "indeterminism" simply means the negation of determinism. So indeterminism is exactly true when determinism is false.]

The logical determinism is based on the following consideration. It is a common assumption among logicians that every statement is true or false. statement will not true or false and them don't stop eitherto be true or false. you are (timeless) true or false. Therefore, for example, the statement "Anna Schmidt will get married on June 20, 2045" is (already today) true or false. If so, it is already clear today whether Anna Schmidt will marry on June 20, 2045 or not. And if that is already certain today, nothing else can happen. In this respect, it has already been determined today whether Anna Schmidt will marry on June 20, 2045 or not.

A related consideration leads to theological determinism. Here the omniscience of God plays the decisive role. If God already knows today what will happen in the year 2045, then it must be clear today - and in this respect it is already determined today - whether Anna Schmidt will marry on June 20, 2045.

The debate about the compatibility of freedom and determinism is primarily about causal determinism.

Causal determinism

What does it mean that a world (in the causal sense) deterministic is? It means that at all times in this world there are conditions that exist in a certain sense establishwhat will happen in the future. At any point in time it is true that the world can only develop as it actually does; there is no point in time when several possibilities of the course of the world are open. How can this intuitive idea be made more precise?

A first possibility is to use the concept of predictability to go out. According to this, determinism is true if and only if:

(D1)The following applies to every point in time: If a 'Laplace demon' (a being with superhuman intelligence) knew the laws of nature and the state of the world at that point in time down to the last detail, then he could predict every event in the future.

The problem with this definition is that it may be impossible to predict self-determined processes for at least two reasons. One reason has to do with what is called "deterministic chaos". These are processes that are completely determined, but in which even the smallest changes in the initial conditions can cause considerable deviations in the states to which these processes lead. In any case, it is often not possible for us humans to determine exactly which initial conditions are present. And therefore we cannot predict what results these processes will lead to, even though they are completely deterministic. (A 'Laplace Demon' may not have this problem, however.)

The second reason is that predictions can have repercussions on the course of the processes whose outcomes we want to predict. Alvin Goldman has come up with the following beautiful example: The aim is to predict what tone an automatic piano will make next. The prediction is made by playing the note that you think will be played next (on a different piano). However, the automatic piano is constructed in such a way that if a certain note is played in its vicinity, it does not play this note but a different note. Obviously, it is impossible to predict in this way which note the automatic piano will produce next, precisely because the prediction leads to it producing a different note - and that of course also applies when when the behavior of the automatic piano is completely determined. (A. Goldman, A Theory of Human Action, Englewood Cliffs NJ 1970, pp. 190f.)

The most common is determinism with the help of the concept of sufficient cause define. A world would then be deterministic if and only if every event in this world has a sufficient cause - that is, if:

(D2)For every event E there is a set of earlier events which together form a sufficient cause for E.

In this reading, determinism is synonymous with that Causal principle, which says that everything must have a sufficient cause.

But what does it mean that U is a sufficient cause for E is? The most common answer to this question is: U is a sufficient cause for E if U is E inevitable or if E take place got toif U is the case. The concept of cause is thus derived from the modal concept of must or of need explained. And that is why it makes sense to understand the term determinism in this way too. However, one must bear in mind that this is only a matter of nomological necessity - the necessity that results from the applicable Laws of nature results. Then one can say that determinism is true if it is at any point in time impossible by natural law is that the world is going differently than it actually is. If you can get this idea with the help of the concept of possible worlds more precisely, the following definition is obtained. Determinism is true (in our world) if:

(D3)Every possible world that completely agrees with our world at a certain point in time and in which the same laws of nature apply as in our world, also completely agrees with our world at all later points in time.

For all those who have difficulty with the concept of necessity or the concept of possible worlds, this definition can also be given a form that only deals with inferential relationships between sentences. Determinism is true if:

(D4)If Z is a complete description of the state of our world at a certain point in time t and N is a complete description of all natural laws in force in this world, then Z and N together logically imply a complete description of the entire history of our world after t .

However, the question here is whether it really makes sense to speak of a "complete description of the state of our world at a specific point in time". On the one hand - according to the theory of relativity - expressions like "the state of the world at time t" must always be put into perspective on a frame of reference. On the other hand, it is - to put it bluntly - quite possible that it is in the world more There are facts than can be expressed through the sentences of a language.

Is Determinism True?

Most of the philosophers before Kant were of the opinion that the truth of the causal principle or the principle of sufficient reason a priori (i.e., through pure thinking without recourse to experience) can be known. Many even thought that the truth of this principle was intuitively evident and could not be doubted at all. David Hume has vehemently criticized this view. He argues that there is no contradiction in assuming the falsehood of the causal principle. So this principle cannot a priori be true. However, Kant himself believes he can show that the causal principle must at least apply in the world of phenomena. Because unless every event has a cause, a unified, objective experience is impossible. Most theorists today, however, agree that the question of the truth of the causal principle or causal determinism is an empirical question. This means that we have to turn to the natural sciences (especially physics) if we want to know whether determinism is true.

But current physics cannot provide any clear information here. General relativity is often classified as "clearly deterministic", but it is misleading. The "singularities" postulated by this theory (e.g. the ominous "black holes") are generally seen as a major threat to determinism. However, these are very controversial aspects of general relativity. Therefore no final judgment about determinism can be derived from it. It is the other way around with quantum mechanics. This theory is mostly seen as "clearly indeterministic", although there are also deterministic interpretations (e.g. the interpretation by David Bohm) which are enjoying great popularity again today. In addition, even with indeterministic interpretations of quantum mechanics, indeterminism takes place primarily on the level of microphysical descriptions of individual particles. In larger systems, stochastic effects smooth out the quantum randomness, so that the behavior of things in the macrophysical world is essentially deterministic. Random deviations from this deterministic behavior are theoretically possible, but so improbable that it is at least no trivial question whether quantum randomness has any relevance to our philosophical interest in determinism.

Ultimately, the only thing that can be said is: the question of whether determinism is true is completely open.


  • Earman, John A Primer on Determinism. Dordrecht: Reidel 1986.
  • Hoefer, Carl "Causal Determinism". The Stanford Encyclopedia of Philosophy (Spring 2004 Edition), Edward N. Zalta (ed.) (URL = http://plato.stanford.edu/archives/spr2004/entries/determinism-causal)
  • Taylor, Richard Metaphysics. 3rd edition. Englewood Cliffs, NJ: Prentice-Hall 1983.
© Peter Schulte, Ansgar Beckermann
Last edit: 2005-03-05 23:00:00