Could the universe or any event within it have occurred otherwise, even if determinism was false?

Question

Could any event have happened differently? Even if the universe was “inherently stochastic”, does this imply that events could have occurred differently? It seems to me that even inherent randomness would just result in true unpredictability in the future but nothing further would be implied.

Even if determinism was false and knowing every possible parameter and cause did not lead to complete knowledge of the future, would this actually imply that the way events turned out could have happened otherwise?

Answer 1

If you mean, "Is there an accessible world, accessible from ours that is, such that determinism is false in our world and in the accessible world things occur that don't occur in ours?" then I don't know that determinism has much bearing on this (if the other world contained the same exact sequence of events, and neither that world nor ours contained said sequence on account of determinism, I'm not sure how determinism is accessibly relevant).

You could move up to another level and ask, "Is there a world accessible from ours where determinism is false?" or then, "Do all worlds accessible from ours, even if they are nondeterministic worlds, contain the same exact events?"

If you mean, "Is it necessary that the events that have occurred, are the events that they are, regardless of determinism?" then in one sense yes, in another sense no: an event has to be what it is relative to its internal identity, but what events exist in the first place is not per se decided by external necessity such that different events could not have occurred.

It would also be helpful to include some reference-fixing for the word "determinism." The generic sense is mathematical: if you have a sequence of variables x over times t_n, the value of x at t_n is the source of the assignment of value to x at t_n+1, e.g. if x_t1 = 1, then there is some f(x) such that f(1₁) changes the upper 1 to something else as the lower 1 increases, etc. If f(x) can map specific inputs to only one output per case, strict determinism is indicated. But so whether f(x) can on some other metaphysical level be itself different from time to time or world to world, is an open-ended enough (schematic) issue such that it seems trivial that two worlds could diverge with respect to f(x) and so diverge per output, or two worlds could diverge on one level but due to subtle "course corrections" (e.g. deeper g(x)'s) they end up aligned on the direct level, etc.

Answer 2

The universe doesn't read philosophy journals. It does what it does, regardless of what philosophers may think.

Answer 3

Even if determinism was false [..] would this actually imply that the way events turned out could have happened otherwise?

The most common interpretation would be that yes, in that case events could have happened in different ways, and only happened the way they happened due to random factors.

But philosophically it depends on the way that determinism "was false" (or how "determinism" is defined in the question). Causal determinism is the most common meaning of "determinism". Causal determinism can be false in several ways which would still make some or all events determined by something.

Even if there were true sources of non-determinism in this universe, those could be too small, too few, too rare, too far away or too "regular" to make events turn out in different ways.

Predeterminism and fatalism are alternatives which do not necessarily require determinism. There can be more such similar nuanced theories that make events non-random yet not decided by the previous state either (but by anything else). All those could be called "Determinism without Causality".

So "events could not have turned out a different way" could be the definition of "causal and non-causal determinism". Then even if causal determinism was false, it is logically possible that non-causal determinism remains true.

Time-travelling in the science-fiction sense is one way of introducing non-causality into a universe, just to give a popular example, same as supernatural telekinesis, teleportation and such. Similarly, prophecy or otherwise "seeing" the future without inferring it from the present as in fantasy and mythology would introduce non-causality. Those could still mean that "things could not have turned out otherwise".

In physics, only quantum phenomena are considered to be possibly non-deterministic in a strict sense, even if many other events can only be described stochastically due to lack of precise measurement methods.

Answer 4

There is no "otherwise". All events have occurred this way instead of any other way. History is fixed, it cannot be edited, rewound or tried again. Only the future consists of uncertain possibilities.

Naturally the history could have turned out differently. All events in history were once mere possibilities in the future. Predetermination is a concept in religion only, not in science. A deterministic universe set up by an indeterministic predeterminator is an illogical, oxymoronic concept.

The current scientific consensus is that the Universe has evolved as a series of probabilistic events. Causality rules, but not with absolute accuracy. The inherent inaccuracy of all events enables evolution, the increase of entropy, the increase of complexity and the arrow of time.