Elliott Sober illustrates (inadvertently) the problem of definitions

One of the problems in most debates and discussions in the problem of definitions. It's common for two opponents to end up talking past one another because they don't agree on what they are arguing about. That's why an important component of critical thinking is to define your terms so that everyone knows what you are defending (or attacking).

But there's more. If you are going to be a good critical thinker, then you have to be aware of other points of view. If there are other, equally valid, definitions out there then you MUST acknowledge them and incorporate them into your argument. You can't, for example, just make up your own definition of words like "noncoding," "junk," or "function," and declare that you are right. Since you know that there are other definitions out there, you are obliged to show why YOUR definition is the only correct one. That's a crucial part of the debate.

If you don't even know that there are other valid definitions then you are not an expert and you should not be pretending to be an authority on the subject. This is why I object to people who argue against the Central Dogma of Molecular Biology without understanding what Francis Crick actually said.

Let's look at a video of Elliott Sober lecturing on "Some Questions for Atheists to Think About." He begins by asking the members of his audience whether they are atheists or agnostics. Apparently, most members of the audience are atheists and ony a few are agnostics.

Next, he defines his terms ...

Theism = God exists
Atheism = God does not exist
Agnosticism = We don't know whether God exists

The lecture is about something called "evidentialism." Elliott Sober claims that the following proposition is true ...

For any proposition, you should believe it only if you have evidence that it is true and you should disbelieve it only if you have evidence that it is false.

He then goes on to show that we can never have evidence that God does not exist. Therefore, "If 'God exists' is untestable, you ought not to be an atheist. You should be an agnostic."

He suggests that all the atheists in the audience should become agnostics because of evidentialism. If I had been in the audience, I would have pointed out that MY definition of atheist is that an atheist is someone who doesn't believe in god(s). My definition is such a common definition that it's part of the Wikipedia article on Atheism. Since I do not need "evidence" to not believe in something, I'll remain an atheist, thank-you very much. My position is perfectly consistent with the proposition about evidentialism.

Here's the problem. Elliott Sober is a prominent philosopher. Doesn't he realize that his argument relies entirely on his definition of "atheism"? Doesn't he realize that his argument is completely useless if an atheist is simply someone who doesn't buy into the God delusion? This sort of thing makes me livid and it makes me wonder whether there's something seriously wrong with modern philosophy.¹

---

1. I am not suggesting that Sober's definition is wrong. He should not be ignoring the fact that many members of his audience don't agree with his definition and that's why they are atheists.