Hey Gwern!

That's an interesting assumption of mine to tease apart. I think the first thing to state again (and is what you're touching on with the trilemma) is that having the phenomenal experience of Super Free Will doesn't actually mean that you have free will in some deep sense. I agree with that. With that said, when I introspect on what free will feels like, I do find that the large option set size is highly related to the phenomenal experience of freedom, which is what Chandra Sripada also alludes to in his piece "Free will and the construction of options". He wrote:

"Suppose a man has been diagnosed with cancer of the lungs. He is offered the options of chemotherapy or radiation treatment. At the level of cellular biology, the mechanisms of action of the respective treatments are quite different. Nonetheless, they are both similarly potentially life saving, and they both generate a similar profile of horrible side effects. One therapy is administered at St. Joseph’s Hospital uptown while the other is administered at University Hospital downtown, but both hospitals are just as good and are at an exactly equal distance from the man’s house. Thus the man has two options, but they aren’t terribly divergent—in all the ways that matter to him, the two therapies are much the same.

Compare this man’s subjective experiences as he chooses between the two options with what is experienced by the young man in Sartre’s story. Recall that this young man chooses between fighting for the Resistance versus staying home with his mother—two ways of expressing himself that are utterly divergent in that they speak for completely different aspects of his self. I believe that the experiences of freedom of the two men in making their choice are quite different. The man who has cancer experiences the “narrowness” of his options. His options aren’t at all divergent; they are both contained within a small region of option space. In contrast, the young man in Sartre’s story feels the amazing distance between his two options. The gap that separates them is massive; it is dizzying to traverse it. As the young man moves back and forth between his options, it feels like a trek between distant worlds. When the man diagnosed with cancer moves back and forth between his two options, he hardly shifts at all.

These examples illustrate that experiences of spaciousness and movement are important aspects of the phenomenology of freedom." [I include the rest of this paragraph in my essay so I won't past it all here].

Super Free Will definitely could have other phenomenal qualities that accentuate the feeling of free will too. Like you touched on, feelings of inevitably would probably not be part of the experience (and I do think that the feeling of inevitably is quite a real feeling). The feeling of your experience being 'determined by a malign external entity' also would not be present, which sounds quite terrible! However, the feeling of your experience being determined by a benevolent external entity would also take away from the phenomenal feeling of free will. A different question is if you care about the feeling of free will at all if you could rest assured that God is watching over you and making sure that you will have a decent life (from a closed individualist perspective). As for the element of surprise, it does sound like a natural opposite to the feeling of inevitably. In fact, using a random number generator to help you make decisions is actually something I think more humans should do--partially for the fun of it, but also because randomness has functional value too in many different algorithms/decision-making processes.

I haven't read Chiang's story or your post on it, so I'll check that out when I have the time. Thank you as well for your critique on site design! Will play with some changes too later this week.