Think of it this way: how do you explain losses in the opportunity-discovery framework? The entrepreneur thought there was a $20 bill on the sidewalk but when he reached down to pick it up, it was gone? In that case it was never there in the first place, so there was no “opportunity” at all. In Kirzner’s framework, the worst that can happen to an entrepreneur is that he breaks even; he either exploits an opportunity or fails to notice one that was there. He can’t make a loss because he doesn’t invest under uncertainty; he simply exploits pre-existing opportunities. (Kirzner has a passage in his 2001 JEL article in which he talks about “mistaken opportunities,” but this seems awkward to me. It’s more straightforward to talk about mistaken actions, i.e., actions that fail to achieve their desired objectives.) To me, the concept of opportunities is redundant and misleading.

Likewise on subjectivity. Opportunities are perceived, imagined, hoped for. They can only “exist” ex post, after profits and losses have been realized. So I agree completely with your second paragraph.

I’m also puzzled about the application of subjectivity. Presumably the projector (sorry, I couldn’t resist) in this case sees an opportunity to profitably apply certain technology and capital equipment to a given use. He might be right or wrong, but it’s still an attempt at opportunity recognition in the sense of Kirzner. There’s nothing subjective about whether it’s going to work or not, since reality always bats last. While the projector’s beliefs about what will happen are of course subjective, this project is going to generate some level of profit if attempted and that outcome is a very objective thing.

If all this is clear in the paper then the above is a big “never mind.”