The Path

Yxo: Damn you! If you hadn't turned left there we wouldn't be lost now.
Ava: Yes, but I did and now we're lost.
Yxo: Alright, but it is true that it wasn't necessarily to be so: right now we could be on the right path.
Ava: Indeed. However, now there's not another place we might necessarily be in.
Yxo: Why? Things could have gone in another way.
Ava: But they didn't.
Yxo: Ok, but if they did...
Ava: Simply they didn't. Now we're here, we could be nowhere else. Future might still be open, but past is surely closed. See that tree? It's there and could be nowhere else. Of course we can imagine a world quite different from our own, in which such tree is on that hill or simply was never born. But here, now, things are like they came to be, and can't be differently. Do you agree?
Yxo: Isn't it easier to simply apologize for having taken the wrong path?
Ava: That is not the point.
Yxo: Still I don't get that point. If now I make a choice, its consequences, amplified by time, will make the two alternative futures diverge. Thus it seems appropriate to counterfactually claim, from tomorrow's point of view, that if today I acted differently the world would be different.
Ava: For sure it is so, but I think it may only have a rethorical function: to remind yourself to be more cautious, and pay more attention to where you turn your car. Time seems to have an unique flow: all the tributaries converge.
Yxo: So that however I deem the world to be in re, deterministic or not, it should be evident that at least our past and present are necessary? Alright. But I still think that it is useful to claim that if yesterday I didn't buy a bag of chips, now I would have ten pence to use that phone cab over here.
Ava: Of course it is: but as an expression of regret, not surely as a metaphysical claim.
Yxo: If I knew you were a counterfactual prescriptivist I would surely have better considered signing our marriage.