If we read the sentences, “He is taller than that,” or “She is from Darien, CT,” or even “\(x^2 \geq y + 4\text{,}\)” we note that they are not statements because their truth values are ambiguous. After all, who is he? What is that? Who is she? Which values of \(x\) and \(y\) are we considering? If we knew the answers to these questions, these sentences would be statements; such sentences are called propositional functions, and we make statements out of them using quantifiers.
