Propositions are the things we express when we use declarative sentences. To build such assertions, we need to use terms in a particular way: a subject term, a predicate term, and a copula to put them together. Constructing propositions out of terms gets us a kind of statement that has a truth-value. Evaluating truth-values by checking against reality and using negation to switch truth-values tells us interesting things about propositions and, in consequence, about the world. But propositions taken in isolation can only get us so far; we want to see what happens when we put propositions together, how they connect, and what further things we can learn by investigating connections between them. This will get us arguments. In the next lesson, we’ll take a look at a specific form of argument we can get by putting propositions together, namely the syllogism. This will turn out to be very important for the rest of our course.