 Note that some of these presuppositions arise by default from specific words that we used. The existence of a time when we wrote the article is a requirement associated with our use of “as”. It is a requirement built into the meaning of the temporal preposition “as”, which has a similar meaning to temporal "while", that in a phrase “as X”, the “X” has to hold at some time. We say that “as” is a presupposition trigger. Similarly, “this” is a presupposition trigger requiring something salient to refer to, the bare plural is a presupposition trigger requiring existence of multiple individuals, and “would” is a presupposition trigger requiring a salient future or hypothetical circumstance.