Is the future set in stone, like the past?
Or is there an infinite multitude of possible futures, determined by events in the present?
It depends upon whether you accept the Copenhagen Interpretation or the Many-Worlds Interpretation.
Some light reading to start with:
Quantum mechanics is not the only thing to look to in this discussion. Perhaps even more to the point, since special relativity implies the breakdown of absolute simultaneity, and thus, does away with the notions of absolute past and future, it can be argued that this implies naturally a block universe view. The most well-known argument along this line is known as the Rietdijk-Putnam argument.
Another way to think of this is the concept of free will. Some people think free will exists because we have many choices that we can make at any point in time. But I disagree. In truth, people only have a limited number of choices, and those choices are dictated by the choices made before, and furthermore those choices are limited by what happened before.
Because the first “choices” you ever made in life–those that happened in childhood–are the ones made available to you solely due to factors beyond your control (like what neighborhood your parents chose to move to, which teachers you happened to get, the diet you’re fed, the way you look and how intelligent you are, et cetera), you could argue that all the subsequent choices that follow also flow from established circumstances. We have some control over how the boat will navigate, but the number of routes available to us is extremely limited compared to the universe of all routes. For instance, I can choose right now to 1) get out of bed or 2)stay in bed. The choice to command a robot to lift me out of bed is not available to me, although it is there for others.
This is a long and drawn out way of saying that “determined by past events” and “infinite number of choices” is a contradictory statement.
If I don’t know the future, then fate is a moot point.
If I do know the future, then I can change it, so again, fate is a moot point.