Determinacy in Feser’s sense just is having an unambiguous meaning. I’ll requote him:
Something is “determinate” in the sense in question here if there is an objective fact of the matter about whether it has one rather than another of a possible range of meanings – that is to say, if it has a meaning or semantic content that is exact, precise, or unambiguous.
This is, again, from one of his posts that I linked earlier. For good measure, you can see one or two further posts to better understand the sense he is using for “determinate”.
Yes. If your thought unambiguously has some meaning to you, it unambiguously has that meaning full stop, and is determinate. The question, then, is how it is possible for your thought to be determinate - what feature of reality makes it the case that your thought has this determinate content.
As I’ve repeatedly said, the context in which the physical structure (be that sound waves, or ink marks, or neuron activation patterns) is embedded is part of the facts about that structure under consideration. It still is insufficient to determinately fix the semantic content. (Again, you can see Feser’s writings to get a better idea of why arguments for semantic indeterminacy come to this conclusion; I think he explains it better than I do. The third link in this comment, in particular, both adds some examples and discusses the generalization.)
I’ve already explained this. Any semantic content that a DNA sequence might have is irrelevant to reproduction, because the chemistry of nucleotides is what is doing all the work. Any semantic content you take a particular bitstring to have is irrelevant to the running of a computer program, because the physics of semiconductors and electrical circuits and such is what is doing all the work. But semantic content is not irrelevant to semantic content itself, so yeah, it is different. This is why your analogies were completely besides the point.
If by interpretation you mean how the program actually gets implemented (what circuits and logic gates and such get used), then that isn’t what I’m talking about, so this too is irrelevant.
You may maintain that. I think you’re wrong about that, but we can let anyone reading along come to their own conclusions.
As in reasons for believing that certain things are true, yes. (Sorry that wasn’t more clear.)
As for whether I am right that none of things (the use of deductive, inductive, or abductive reasoning; moral and ethical beliefs; high-level metaphysical conclusions that radically impact how any empirical evidence will be interpreted) can be justified purely empirically, I think that is getting beyond the scope of this discussion. (I had to raise it to explain my disagreement with your dismissal of the argument, but I’m trying not to get drawn into a whole new topic!) I have discussed the general idea on this forum before, at least somewhat.
I think I am getting near the point where I have said all I have to say in this thread, so this may be my last response (unless any of my interlocutors bring up something that I really want to address). I appreciate the discussion, everyone, thanks.