This is mostly just a summary of what look to me to be the main points of van Inwagen's first chapter. I have added just a couple of comments of my own
Metaphysics is "the study of ultimate reality."
"reality" contrasts with "appearance." This distinction in turn comes from the distinction between apparent facts and real facts (e.g. the sun apparently revolves around the earth, but really the earth is rotating on its axis).
what about "ultimate"? There may be chains of appearances (which presumably get increasingly real as you get nearer the bottom, so to speak). Ultimate reality is whatever is at the bottom of the chain of appearances: the reality that's really real, not just more real (closer to the truth) than some appearance.
The ultimate truth about what? About three things:
Metaphysics must be distinguished from physical cosmology and from revealed theology.
van Inwagen clarifies the nature of metaphysics by contrasting two overall metaphysical pictures, one associated with the Medieval period and one with the nineteenth century:
|Medieval Theism||Nineteenth-Century Materialism|
|1. What is the World like, and what does it contain?||The World consists of God and God's creations. God is infinite, eternal, and nonphysical. God's creations are finite; some are physical and others are nonphysical.||The World consists entirely of particles in motions determined by fundamental physical laws. Everything else is just collections, actions, or properties of these particles.|
|2. Why does the World exist?||God exists necessarily (i.e. it would be impossible for God not to exist). Everything else exists because God created it and sustains it.||The World is eternal, since it consists of matter, which can be neither created nor destroyed. [remember, this is nineteenth-century materialism, not twenty-first-century materialism!] We can't ask why it came into existence, because it didn't.|
|3. What is our place in the World?||We were created by God to love and serve him. Each of us has a purpose determined by God.||We are "complex configurations of matter." Our existence is ultimately due to chance, and has no larger purpose (beyond our own goals or purposes).|
In the interest of full disclosure, van Inwagen says his own views are closer to those of medieval theism than to those of nineteenth-century materialism.
According to van Inwagen, in philosophy there is no "information" and there are no "established facts." (I'm not entirely sure what he means by "information" -- perhaps uncontroversial knowledge? He says there may be philosophical knowledge but it's not "information." Similarly, there may be philosophical facts, but they are not "established.")
Why are there no established facts in metaphysics? Possible answers:
The parable of Alfred
How will Alfred teach a subject with no established facts (and how should his students respond)?
Here's my insight for the day. What is expertise in philosophy? In most fields, we rely on experts as guides to the truth. If I'm not sure what the distance from the earth to the moon is, and an expert astronomer tells me that it's 384,400 km (on average), I don't feel any need to try to figure out how to measure it myself. An expert astronomer is one who knows the truth about a lot of astronomical matters.
On the other hand, if you don't know whether physicalism is true or not, and an expert philosopher tells you it is (or isn't), you shouldn't simply believe him or her! You should think through the arguments yourself. This doesn't mean that there's no such thing as philosophical expertise. But in philosophy, expertise is a matter of knowing a lot about the arguments pro and con, the history of discussion of the issue, etc.
Possibly there are some other disciplines that are sort of like this? If an expert economist makes a prediction about what will happen to the economy, you shouldn't necessarily take his or her word for it. And even more so if an expert political scientist tries to tell you who will win an election!