Hussar
Legend
Sorry, I think you misunderstood.That's a rather particular definition of SF and not one I've encountered before in any discussion of what it means to be SF including discussions that define SF by theme.
And I'm not sure you can convince me of it, because I'm not sure you can convince me the theme of "The Alien Way" is that we are defined by our free will, unless you can include the rejection of the idea that we have free will as being also an explanation of what free will actually means. And for that matter, it's not clear to me that Dune claims that any character in it has free will either. Or "Leviathan Wakes". And that means that the theme you've defined is so broad, that it would be hard pressed to claim any book isn't science fiction. Hemingway's "The Old Man and the Sea" for example.
It's equally not clear to me that issues of free will are at the heart of everything I'd want to call science fiction, say the "Culture" books by Ian M. Banks.
I said that the primary theme of Dune was an exploration of free will in the face of prescience. Not that SF's only theme is free will. I'm not quite sure how you made that jump.