 Suppose we have a set of beliefs, and we wonder what the answer to the ontological question ‘Are there numbers?’ is, assuming (O4) tells us this is the ontological question about numbers. One strategy to see whether our beliefs already commit us to an answer of this question is as follows: first, write out all those beliefs in a public language, like English. This by itself might not seem to help much, since if it wasn’t clear what my beliefs commit me to, why would it help to look at what acceptance of what these sentences say commits me to? But now, secondly, write these sentences in what is often called ‘canonical notation’. Canonical notation can be understood as a formal or semi-formal language that brings out the true underlying structure, or ‘logical form’ of a natural language sentence. In particular, such a canonical notation will make explicit which quantifiers do occur in these sentences, what their scope is, and the like. This is where formal languages come into the picture. After that, and thirdly, look at the variables that are bound by these  quantifiers.[3]  What values do they have to have in order for these sentences all to be true? If the answer is that the variables have to have numbers as their values, then you are committed to numbers. If not then you aren’t committed to numbers. The latter doesn’t mean that there are no numbers, of course, just as you being committed to them doesn’t mean that there are numbers. But if your beliefs are all true then there have to be numbers, if you are committed to numbers. Or so this strategy goes.