If he didn't use the word "merely," this would be an even more amazing rationality quote than it already is.
I don't think it's very good either way. It's just a flat statement - presumably it was the thesis or conclusion to some long chain of arguments proving it. But as a quote? It is not very memorable, or witty, or a novel argument or any of the usual criteria I judge our quotes on.
Here's the new thread for posting quotes, with the usual rules: