Source: p 50, What Does It All Mean? A Very Short Introduction to Philosophy (1987) by Prof. Thomas Nagel
When you say you could have had a peach instead of chocolate cake, part of what you mean may be that it wasn't determined in advance what you would do, as it is determined in advance that the sun will rise tomorrow. There were no processes or forces at work before you made your choice that made it inevitable that you would choose chocolate cake.
That may not be all you mean, but it seems to be at least part of what you mean. For if it was really determined in advance that you would choose cake, how could it also be true that you could have chosen fruit? It would be true that nothing would have prevented you from having a peach if you had chosen it instead of cake. [1.] But these ifs are not the same as
saying you could have chosen a peach, period. [🔚] You couldn't have chosen it unless the possibility remained open until you closed it off by choosing cake.
What exactly are the IFs? Which if-clause(s) does Nagel reference?
How is 1 true? How do the If-clauses differ from
saying you could have chosen a peach?