If determinism is true, would that mean that in a scientific theory, everything that is a theoretical possibility actually happens? I apologize if this question is similar to previous questions of mine.

  • 1
    The answer to this question has nothing to do with whether determinism is true. It depends on one's position on modality, see actualism vs possibilism. – Conifold Nov 3 '17 at 22:58
  • No. you could imagine a universe with a single non-moving particle. That's deterministic but not every possible thing happens in that universe. In any deterministic universe, there is a specific list of things that happen. An accurate scientific theory may predict other things could happen, but the conditions in the deterministic universe are never valid for that to actually happen. – barrycarter Nov 4 '17 at 17:27

If determinism is true it does not follow that everything that is logically possible happens. Determinism at least on one reading rules out any events other than those that actually (deterministically) occur. This does not exhaust the realm of logical possibility. It is logically possible that Donald Trump is a robot; the possibility is coherently conceivable = logically possible. This is so even though he is not actually a robot and if determinism is true, cannot be or have been anything other than he is, namely a human being.

Posssible worlds introduce another angle. In the actual world, or this actual world, if determinism is true then given the laws of nature and initial conditions, if X doesn't happen then X could not have happened and in this sense is not or was not a theoretical possibility. A modal realist about possible worlds can hold that there are other worlds, real and therefore possible, in which the laws of nature or initial conditions are different and an event, deterministically and theoretically impossible in our actual world, is possible and actually happens.


I think if determinism is true it means that everything is fact, the past, present and the future. We normally only associate fact with our observed history through memory of it. But Determinism means that we experience the eternal fact by the passage time we are subject to. If we were able to remember the future though our journey would be unnecessary as when we are brought into this world the passage of time would be unnecessary since our life of experience would be known if indeed things are determined and that fact is allready a determining factor. So I think what we experience is a function of memory and fact, and time simply allows us to experience the fact of our lives. Well that's my two pennies worth and humble opinion

  • @Geoffrey Thomas it is certain in a deterministic world that someone will have a theory about how the method in which it is determined. And it is certain that this theory will be never correctly proved by testing it because it would result in a method of determining the future and gaining knowledge of events by it before those events happened. Surely that knowledge would result in contradicting the world's deterministic nature by being able to falsify the deterministic nature by the use of it and ultimately disprove the method you have come across . Its a logical tye up. – user29363 Nov 4 '17 at 22:50

"Is nothing a theoretical possibility unless it actually happens?"

Is this a question about what "theory" means? The philosophic meaning of theory is, very roughly speaking: orientation, something to meditate over concerning what the world is. From Plato up to the modern age. When the sciences took over the word theory, it began to mean something that can be applied. So, if one has, say, some reliable data about probabilities, say, actuarial tables, one can then apply them. There they give reliable predictions. The phrase "theoretical possibility" has to connect to a Sample Space where data points can occur during experimentation. So, if you want to say that Determinism means everything will happen, you must add to the conception of determinism an infinite time, or, whatever the conditions for everything to happen must be. That will be your Sample Space. In which all events are understood through the conception.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.