The future is contingent and not physically determined by the past and laws of nature, nor is it necessitated by logical or theological considerations.
But the very earliest philosophers were concerned that determinism and necessity might imply that there is but one possible future. Leucippus stated the first dogma of determinism, an absolute necessity which left no room in the cosmos for chance.
"Nothing occurs at random, but everything for a reason and by necessity."His fellow atomist, Democritus, thought that strictly causal laws of nature would free man from control by capricious gods and arbitrary fate. He postulated that everything in the universe is reducible to matter, "atoms in a void," that the motion of the atoms is completely determined by physical laws, and that includes the human mind. Diodorus Cronus was a member (or perhaps a late follower) of the Megarian School, whose arguments about the truth and falsity of statements about the future influenced Aristotle. The so-called "Master Argument" was apparently first formulated clearly by Diodorus. He argued that the actual is the only possible. He observed that if something in the future is not going to happen, it was therefore true in the past that it would not happen. From this correct observation, he mistakenly claimed that the existence of true statements about the future imply that the future is already determined. The Master Argument was central in the Hellenistic debates about determinism, as shown by Cicero's descriptions in On Fate. The Master Argument is closely related to the problem of future contingency, made famous in the example of Aristotle's Sea-Battle in De Interpretatione 9. Aristotle thought statements about the future lack any truth value. They are neither true nor false until the future time when they become true or false. Modern philosophers like J. J. C. Smart like to think that the future is "already out there" in the relativistic space-time continuum of the "block universe." Modern determinists/compatibilists on free will like to argue that just as the past cannot be changed, so the future cannot be changed. "Change it from what to what?," says Daniel Dennett. But note that the truth value of a statement made in the past can be changed when an event it describes does or does not happen, showing that some aspects of the "fixed past" (i.e., the truth values of past statements) "actually" have some changeability (when their potentials become actual).
Information Philosophy and Future ContingencyThinking about the problem in terms of the growth of information provides the clearest resolution of the problem of future contingency. Information is not a constant of nature. The cosmic creation process is constantly creating new information. When information is created, there is always an irreducible chance element since it is quantum processes that form stable new information structures. Some information about future events does not come into existence until the potential events become actual. It is at that time that statements about the future acquire their truth values. Aristotle did not think in information terms, but he had the right answer, one that disturbs modern logical positivists and analytic language philosophers, as shown by Richard Taylor's faux argument for Fatalism in the Psychological Review. Note that Fatalism is a form of determinism. It is the simple idea that everything is already fated to happen, so that humans have no control over their future. But also note that Fate (personified) has arbitrary power and need not follow any causal or otherwise deterministic laws. It could include the miracles of omnipotent gods, in which case future contingency returns. Note further that the gods' omnipotence contradicts the theological assumption that gods are omniscient. They cannot be both. That is a logical contradiction.