I’ve occasionally suggested that I don’t do metaphysics. One of the comments to my previous post took me to task over that, saying that it was an example of doing metaphysics and that I was therefore contradicting myself.
Such literalism. This kind of quibbling is part of why many scientists are dismissive of philosophy. Here, I’ll try to clear up that confusion.
What I’m against
Of course, every thinking person will do some thinking about metaphysical questions, self-included. We can’t help it. We are confronted with these questions, posed by others. They may be questions that have no answers. But we will think about them anyway.
What I oppose, is using metaphysical assumptions as a basis for other reasoning, such as reasoning about knowledge.
Mathematics
I’ll illustrate the point with mathematics. There, I avoid platonist assumptions. I usually consider myself a fictionalists (mathematical entities are useful fictions). And I suppose that, technically, fictionalism is considered a metaphysical position. But the point of fictionalism is to avoid making assumptions about the existence of mathematical entities by treating them as fictions.
Incidentally, I did not choose fictionalism to avoid metaphysics. Rather, fictionalism seems to be a pretty good account of how I have always thought about mathematics.
In practice, fictionalists and platonists do their mathematics in about the same way. For most of what a mathematician does, it makes no difference. However, a convinced platonist is likely to say that there is a fact of the matter as to whether CH (the continuum hypothesis) is true. By contrast, I doubt that there is a fact of that matter and suspect that the status of CH is an artifact of which axioms we choose.
Laws of nature
A particular issue that came up in the previous post, was that of laws of nature.
The view that many hold, is that there are fundamental laws that govern the universe. These laws might be unknown at present. It is assumed that they are something like governing rules, and that the are “law like” which is usually taken to imply that they have a mathematical structure.
Most philosophers of science, and probably most scientists, see science as an activity engaged in an attempt to discover these putative laws of nature. It is said that they do this by means of induction.
For myself, I doubt that there are any such metaphysical laws of nature. I see no evidence that there is anything mathematical about our universe. Yes, we do have laws of physics, but I see those as pragmatic constructs that enable us to describe our world and to control our own interactions with our world. I see no basis for taking them to be fundamental laws of nature.
Conway’s “Game of Life”
To illustrate my point, let’s look at Conway’s Game of Life. Quoting the Wikipedia entry:
The “game” is a zero-player game, meaning that its evolution is determined by its initial state, requiring no further input.
We can think of the game as a kind of artificial world, and we can think of John Conway as a designer god for that artificial world. The game progresses by following completely deterministic rules. We might well say that those rules govern the world of that game, and are the laws of nature for that artificial world.
When people discuss the game, they often talk about features such as gliders and glider guns (that appear to generate gliders). So we can perhaps think of the gliders and glider guns as major features of that world.
When we look at Conway’s rules (the laws of nature for that artificial world), we see that they say nothing at all about gliders or about glider guns. So those laws of nature are the wrong kind of thing for discussing the major features which are the gliders and the glider guns.
But it is worse than that. Not only do the laws say nothing about gliders, but it is not even possible to logically deduce from those laws that there will be gliders and glider guns. And this is in spite of the fact that the game is completely deterministic.
I should clarify that. Some people might believe that we could deduce gliders from the laws. However, the laws themselves are not sufficient to deduce that there would be gliders. We would also need to know something about human perception. What makes them gliders, is that we perceive them as gliding. There is nothing in the rules that dictates how we should perceive them. That we perceive them as gliders is a psychological fact about us, rather than a fact about the game of life itself.
Lessons for us
The lesson for us, is that even if there are fundamental laws of nature that govern our universe, there is no reason the expect that such laws would be useful (or even meaningful) to us. Those putative laws probably say nothing about what we see as major features of our world.
If there are laws of nature, they probably say nothing at all about mountains or rivers or oceans or planets or solar systems. What makes something a river or a mountain is defined by our biology and our culture, rather than by putative fundamental laws of nature.
The Heretical Philosopher 