Again, both you and Britannica are trying to limit what "can happen" to what "will happen". It is a standard error in the formulation of determinism to suggest that "we could not have done otherwise" when it is only the case that "we would not have done otherwise".
The distinction is meaningless. As there are no alternate actions within a deterministic system 'would not have' is equivalent to 'could not have' done otherwise. The relevant point here being: there are no alternate actions within a deterministic system. Which is not according to me or Brittanica, but how determinism is defined. Not as defined by me, or Brittanica, but just how determinism works by definition, which includes your own.....
Claiming that the distinction between "can" and "will", and between "actuality" and "possibility", are meaningless is nonsense. There are multiple things that we "can" do, but only one thing that we "will" do. We consider multiple possibilities before settling upon our actual vacation, or car, or home, or mode of transportation, or college, or career, or dinner, etc.
The notion of multiple possibilities is essential to human creativity and invention as well as to choosing. And it continues to do its work in a world of perfectly reliable cause and effect, by shifting to a different language and logic specifically evolved to deal with such matters.
And that is why the claim that "we could not have done otherwise" creates a sense of
cognitive dissonance ("a perception of contradictory information"). If, a moment ago, you tell me that I can choose chocolate or vanilla, and then I choose vanilla, and then you tell me that "you could not have chosen chocolate", I would ask whether you are lying now or lying then. If it was true a moment ago that "I CAN choose chocolate", then how can it be true now that "I COULD NOT have chosen chocolate"? COULD is simply the past tense of CAN. So, if "I can" was ever true at some prior point in the past, then "I could have" will forever be true in the future when speaking of that same point in the past.
On the other hand, if you claim that "I WOULD NOT have chosen chocolate", then I would readily agree. I had my reasons for choosing the vanilla. And until those reasons change I will not choose chocolate. So, we do not get any cognitive dissonance with "would not".
Hard determinists embrace a myth about ordinary people. They suggest that people who complain about "could not have done otherwise" are holding some metaphysical view of a supernatural ability to step outside of cause and effect. Hogwash. They are simply objecting to the cognitive dissonance created by an implicit contradiction between claiming "I can" a moment ago and now claiming "I could not have".
When someone decides whether to order the Salad or the Steak for dinner, and they choose the Salad, they can truthfully say "I chose the Salad, even though I could have chosen the Steak". Both "I chose the Salad" and "I could have chosen the Steak" are matters of fact, and there is no contradiction between them.
It is truly unfortunate that many determinists still conflate what "can happen" with what "will happen", when simply using a bit more care with our words would eliminate the contradictions that create the cognitive dissonance.
It may help to clarify why "can" is a logical necessity within the choosing operation:
Whenever choosing between X and Y begins, it is logically necessary that "I can choose X" is true and "I can choose Y" is also true. If either of them is false, then we only have one option and we do not initiate a choosing operation. For example:
If "I can choose X" is false, then we never consider X to be a real option, and we simply do Y without further consideration.
If "I can choose Y" is false, then we never consider Y to be a real option, and we simply do X without further consideration.
In either case,
we never begin choosing without first having two real possibilities.
It is only after we know for certain that "I can choose X" and "I can choose Y" are both true that we begin evaluating our options, to decide which one we will choose.
At the end of the choosing operation, we will have one thing that we will choose, and one thing that we could have chosen but decided not to.
But there is never a point where anything other than what has been determined can happen. Nothing else can happen.
Wrong! There is never a point where anything other than what has been determined
will happen. Nothing else
will happen.