It's not what I need to think. It's not about what I claim. It is precisely how you yourself define determinism.
That is what determinism means. That events proceed without deviation, as determined, therefore a matter of natural necessity, not choice
The problem is that you are drawing a figurative implication from determinism while I am taking it literally. If it is the case that all events proceed without deviation as a matter of natural causal necessity, then our choosing, along with every other event, is causally necessary from any prior point in time.
Every aspect of that choosing is equally causally necessary, and must proceed without deviation. Each thought and feeling we experience while choosing whether to order that Steak or to order the Salad instead, is causally necessary. Each consideration as to which option best accomplishes our dietary goals is causally necessary. Each recollection of what we had for breakfast and lunch earlier in the day is causally necessary. Each value judgment we apply to our options is causally necessary. And then, finally, the choice itself is found to be the necessary result of all of these thoughts, feelings, and considerations.
This event is called "choosing". And it is a logical operation performed both locally and inevitably, in time and place, by our own brains. There is no science, neuroscience or physical science, that can validly deny that this event is actually happening, exactly as it does happen.
The notion that this event is not "really" choosing is the result of figurative thinking. But the event really and literally is choosing.
Choice, by definition, entails selecting between two or more realizable options.
Choice
1. an act of choosing between two or more possibilities.
Exactly. We objectively observe the many possibilities on the restaurant menu. The restaurant is willing and able to prepare for us any meal listed. And we are physically able to order any item we choose, by simply speaking the words, "I will have that for dinner, please", to the waiter. Every item is something that we actually can order.
Every option on the menu is realizable, even though only one will actually be realized.
Choosing is a real process that we ourselves really perform. All of the options on the menu are realizable possibilities.
Deterministic causal necessity does not actually alter any of these facts.
Determinism: no deviation, no possible alternatives, no 'act of choosing between two or more realizable alternatives.'
But there you are denying the fact of choosing, and the fact of two or more realizable alternatives. And on what do you base this denial?
Well, it seems to you that, if every event is causally necessary, then it is AS IF choosing isn't really happening. But there it is, happening right in front of us.
And it seems to you that, if every event is causally necessary, then it is AS IF the items we did not choose were never "really" possible. But the actual notion of what possibilities are, things that may happen but then again may never happen, assures us that every item on the menu was a real possibility, even if it was never going to be chosen and never would happen.
So the whole notion that deterministic causal necessity implies the absence of choosing or the absence of multiple possibilities, is based upon figurative thinking.
Just for emphasis; there are no 'two or more realizable alternatives, because determined events progress without deviation.
Just for emphasis, the fact that events progress without deviation does not eliminate any alternative or make it unrealizable. The alternative may or may not be realized. That's what "realizable" means. It does not mean that the alternative will be realized, but only that it could, under certain circumstances, be realized.
And that is really the whole point of the notion of possibilities. We don't always know in advance what will happen, but only what can happen. The notion of "can" or "possibility" accommodates that lack of foreknowledge, giving the mind a way to cope with its uncertainty in a productive way. When we do not know what will happen, we imagine the things that can happen, to prepare for what does happen.
Confusing what "can" happen with what "will" happen disrupts this logical mechanism. Limiting what "can" happen to what "will" happen breaks the mechanism entirely, leaving us floundering in paradoxes. And that is what can happen if we take our figurative statements literally.