 Okay, so we want to understand what Aristotle is doing here in this little excerpt. He's trying to answer this problem of metaphysics. And for him that means answering two different questions. What does it mean to exist and why does the thing exist? These are the two questions he's trying to answer. The first part of the problem of metaphysics is what does it mean for something to exist and the second part is why does the thing exist. His answer to the first part is pretty straightforward is substance. Substance is what exists. If it's not a substance, it doesn't exist. And we might further ask Aristotle what's a substance and he says, well, it's a composite of form and matter, form and matter. And why a thing exists? For him that's going to be the four causes. The four causes and we'll get to the four causes next week or next time. We'll get to the four causes. And in the meantime, let's just focus on the first part of the problem of metaphysics. What does it mean to exist? It means to be a substance. That's what existence is. It's to be a substance. Now his answer is a little different to Plato of course. Plato thinks existence is explained with form and that's what it means to really exist is to be form. Aristotle is a bit more interested in the particular things. Plato thinks the highest form of existence is this top form, the being, the good, the true and the beautiful. Aristotle is like, this thing here, this thing here that I'm sitting in front of, that's pretty real. I don't need to appeal to some form for that. All right, so let's take a look at what Aristotle has to say in terms of substance and even this relationship between matter and form.