https://maximummathematics.com/books/foundational-mathematics/proof/universal-specification/index.htmlThroughout our discussion of arguments so far, we haven’t made use of any quantified statements — though we devoted several sections to quantifiers in the previous chapter, so we certainly got some mileage out of them there. Here, we start to discuss how quantified statements can be used in arguments. The reason we want to do this is that many of the results we’re going to come across are stated in the language of quantifiers. For example, consider the Pythagorean Theorem:Hugoen-US