History of Modern Philosophy
Terminology
There are often considered to be four main “branches” of philosophy:
Metaphysics and Ontology: (In some contexts, these two terms have slightly different meanings: Metaphysics is the study of reality, while Ontology is the study of existence. But we will use the terms interchangeably in this course.) Metaphysics and Ontology are concerned with questions about what is ultimately real , or about the fundamental nature of reality. What is there, really ? Examples: Is there a God? What, exactly, are numbers? Do minds exists independently of bodies? Do bodies exist independently of minds? Do we have a free will?
You might think that it is the business of science (not of philosophy) to answer these questions.
Perhaps so--Perhaps not. But this itself is a philosophical question!
Epistemology: Epistemology concerns the study knowledge. What does it mean to know something? How is this different from simply believing something that happens to be true?
How do we (how ought we) justify our beliefs? What kinds of reasons should we accept for believing that something is true? What kinds of things can we have knowledge of or about? In this course, epistemology takes center stage. The people we look at will have different metaphysical views (views about the ultimate nature of reality), but these different views will stem from their different epistemological positions. This should not be surprising: after all, if we are going to talk about what is ultimately real, aren’t we going to need to defend the idea that we are justified in believing such things? The idea that we need to understand something about knowledge before being in a place to defend claims about the ultimate nature of reality is part of what Descartes is getting at when he titles his work (the one we will be reading) Meditations on
First Philosophy . Descartes is claiming that epistemological questions must be addressed before other kinds of philosophical questions.

Value Theory : (Sometimes this simply called “Ethics” or “Moral Philosophy,” because the kinds of values that get most of the discussion are moral or ethical values. But the more general term, “Value Theory,” also includes artistic or aesthetic value.) What gives things value? What makes them good? These are very general questions, because there are different kinds of value, and different ways in which things can be good (or bad). A big part of the discussion under this topic has to do with the nature of morality. How should I live? What things are important?
What makes certain things or behavior morally right or morally wrong? Is this just a random list, or is there something all these things have in common? And what about artistic or aesthetic value? What is beauty? Is this really “in the eye of the beholder,” or is there something
“universal”or “objective” about the nature of beauty?
Logic: Logic is the study of the proper forms of reasoning. How do we distinguish good reasoning from bad reasoning? Logic (at least until advanced levels) is more of a skill than a subject matter. Just as astronomers (at some point in the past) had to learn lens grinding to learn about heavenly bodies, so must philosophers learn logic in order to reason about philosophical issues. We simply have no other tools at our disposal. If we could answer a question by looking through a telescope, that’s what we would do. (And that’s why astronomers must learn something about telescopes.) But the only tool philosophers have is reasoning, and so logic has a special role in philosophy: it is a skill we must hone in order to be able to make any kind of progress in answering philosophical questions.
So, those are the main branches of philosophy. In this course, our primary concerns will be epistemological and metaphysical. That is, we will look at various positions about what we can know, and the implications these views have for what we might have to say about what is ultimately real. We won’t study logic directly, but it will be the tool that we use to pursue the questions we do directly tackle. But we really won’t spend any time in this course on the moral, political, or aesthetic positions of any of the people we will study. That doesn’t mean they don’t have any. They do, and some of those views are quite important. But there is only so much we

can do in one course, and the History of Modern Philosophy is generally taught as an introduction to the epistemological questions that are part and parcel of the “scientific revolution” of the 17th and 18th centuries.
One last bit of terminology for today. There are (at least!) two major schools of thought regarding the nature of knowledge that will be represented in the philosophers we will study:
Empiricism: Empiricism, briefly, is the view that all knowledge comes from sense experience.
Rationalism: Rationalism is the view that at least some knowledge comes from reasoning, independently of sense experience.
One thing I would stress about these two schools of thought concerns what it means to say that knowledge does (or doesn’t) “come from” sense experience. The question here concerns where knowledge comes from, not where beliefs come from. Empiricism and rationalism are not psychological theories about we come to have ideas or about how human beings actually learn things. They are theories about how beliefs can be justified . We may believe many things, but at some point, we may want to gives reasons, justifications, for these beliefs. Empiricists say that justification of a belief must always end in some kind of appeal to sense experience. (For example, “I know that P is true because I saw Q.”) Rationalists deny this, and say that, at least sometimes (maybe always), a belief can be justified by pure thinking or reasoning, without being tied to what anyone anywhere has (or even could) experience through the senses. Rationalists don’t (typically) believe that we are simply born knowing things. Rather, they claim that our knowledge of certain things is not based upon anything we have learned through sense experience. Again, the issue is not how we came to have a certain idea , but we know that it is true. We will talk more about this in class, but for now, jus ask yourself: how do you know that
2+2=4? Note, I am not asking how learned this. Maybe your first grade teacher was the first person to tell you this. I am asking how you know that it is true .

Finally, let me say a little something about the title of this first work we are studying, Descartes’
Meditations on First Philosophy . What in the world is “first philosophy?” There is a bit of history that I won’t go into here, but Descartes believes that questions about what we can know are the most fundamental of any of sorts of philosophical questions. After all, when I affirm any claim (say, about what is ultimately real), I am implicitly claiming that I know that this claim is true, that I have good reasons for believing it. So, before we can start making claims in other areas of philosophy, Descartes thinks, we must begin with a discussion of what we actually know . For Descartes (unlike, say, the ancient philosopher, Aristotle), epistemology is “first philosophy.”
Secondly, why are these called “meditations?” In part, I think this reflects the nature of his inquiry: he will be “thinking aloud”or “meditating on” these questions. He will ask questions, and consider the pros and cons of various answers as he goes along. But I think another important aspect of calling these “meditations” is that we are supposed to be doing them with
Descartes. That is, he is not simply telling us what (he thinks) is true, but is engaged in a process of thinking that we can engage in with him. As we shall see, there is something essentially “first person” about Descartes’ discussion. We are not asking about what is possible for someone else (for Descartes) to know: we, each of us, must be asking what I can know. Each of us must start within ourselves. Whether or not there is anything “outside” us is not something we can take for granted at the start, but must itself be justified. So, as you are reading Descartes, keep in mind that he expects you to be doing the reasoning with him, and that you will reach the same conclusions, regarding yourself, as he reaches about himself. This is philosophy you must do , not just learn about.