Fate

In plain terms

Fate says the outcome is fixed regardless of the route. Determinism says the route is fixed too, and that your actions are part of it.

The difference matters because only the first supports the conclusion people draw. If you will recover whether or not you call the doctor, then calling is pointless - that is the ancient lazy argument, and it is a good argument against fate.

The Stoic answer is that events are co-fated. It is not fated that you recover; it is fated that you recover having called the doctor, and the calling is part of the sequence rather than an optional addition to it. Remove it and you have described a different sequence.

Which saves the position and gives up most of what makes fate sound like fate.

As a philosopher would put it

The Stoic heimarmenē is an unbreakable causal sequence identified with providence and with the rational order of the cosmos, so fate and reason coincide. The lazy argument - argos logos - presses that if outcomes are fated, action is superfluous, and Chrysippus's reply distinguishes simple fated events from co-fated ones, in which the outcome is fated together with the means.

The theological version is foreknowledge rather than causation. If God knows infallibly what you will do, it appears you cannot do otherwise. Boethius's answer is that divine knowledge is timeless rather than prior, so it does not precede and constrain; Ockham's is that God's past knowledge is only soft-past facts about the future; Molina's middle knowledge posits divine knowledge of what any free creature would do in any circumstance.

Islamic qadar generated a parallel and equally sharp debate, with the Muʿtazila defending human power over acts and the Ashʿarites developing kasb, acquisition, in which God creates the act and the agent acquires it.

What is actually disputed

Whether fatalism follows from anything.

The logical argument for it needs only bivalence: if it is true now that you will do X tomorrow, then you will, and nothing can make it otherwise. Aristotle's sea battle passage worries about exactly this, and one response restricts the excluded middle for future contingents.

The standard modern reply is that the argument confuses the necessity of the consequence with the necessity of the consequent: given that you will do X it follows that you will do X, and that says nothing about whether the act is up to you.

The theological version is not so easily handled, and the Boethian, Ockhamist and Molinist answers each pay somewhere - timelessness makes divine action hard to state, soft facts are hard to specify, and middle knowledge posits truths about what free agents would freely do with no obvious ground. None commands assent.