Let's think about the following modal sentence:
1. My expository skills could be better than they are.
(1) is a modal sentence because of the presence in it of the modal word 'could.' Whether or not you agree with me that (1) is true, you must concede that (1) has a definite meaning understandable by any competent speaker of the English language. (1) is a bit of ordinary, grammatically correct English: there is nothing extraordinary or 'philosophical' about it. Not only does (1) have a definite meaning, it has exactly one definite meaning: no question of ambiguity arises. One cannot say that (1) is meaningless or incoherent or ambiguous. Compare (1) with the nonmodal
2. My expository skills are better than they are.
(2) is plainly incoherent for reasons that need no belaboring. And anyone who understands English will instantly discern the difference between (2) and (1).
Now the question is whether sentences like (1) are truncated counterfactual conditionals. Of course, there is nothing conditional about (1) as it stands: it is a categorical sentence. It says straight out that my expository skills have a certain property, the property of being possibly such as to be better than they actually are. But one might argue that (1) is really a counterfactual conditional in disguise, or that it is elliptical for some counterfactual conditional or other, or that it needs completion, or that it needs to be set in a wider context to be intelligible. Now I do not deny that there are counterfactuals in the vicinity into which (1), suitably modified, can be embedded. Here are a couple:
3. Were my expository skills better than they are, I would have convinced Dave by now.
4. Had it not been for a misspent youth, my expository skills would be better than they are.
Consider (4) in its relation to (1). Were I to assert (1), a member of my audience could ask: what would have had to have been the case for you to have better expository skills than you in fact have? In reply, I could say: "I 'devoted' too much time to sex, drugs, and Rock & Roll, and not enough to my studies. Had it not been for a youth wasted on sex, drugs, and Rock & Roll, , my expository skills would be better than they are." (Memo to the curious: I am not revealing any biographical details here; these are just examples rigged to make a philosophical point.)
I do not deny that (1) can be expanded into some such counterfactual as (4). (You will notice, however, when (1) is placed in the context of (4), the 'could' gives way to 'would.') But the question is whether modals like (1) MUST be expanded into counterfactual conditionals like (4). This is what I deny. (1) is perfectly intelligible by itself: it can be, but need not be, embedded in a wider counterfactual context. What does (1) say when construed as a semantic stand-alone (as opposed to a sentence that needs to be embedded in a wider context to be intelligible)? It says that it is broadly-logically possible that my expository skills be better than they are. That is not only perfectly intelligible, but also true.
To see the point more clearly, consider a modal sentence that cannot be embedded in a wider context given certain assumptions to be spelled out:
5. The physical universe could have not existed.
Let's assume that reality is exhausted by the physical universe: all there is is the physical universe and what it contains. If so, then there is no wider counterfactual context into which to embed (5). We could not then say, for example,
6. Had God not created the physical universe, then it would not have existed.
Assuming that all that exists is the physical universe, that there is nothing outside it that could in any way cause or condition it, the assertion of its modal contingency -- which is what (5) asserts -- cannot be embedded in any wider context. And yet (5) is perfectly intelligible. It says that the physical universe does not exist of broadly-logical necessity, but is broadly-logically contingent: it exists, but it is possibly nonexistent.
Now either you understand the last sentence or you do not. If you do not, then I pronounce you modally blind, and the discussion ends.