Who said You can't reason someone out of a position they didn't reason themselves into?

I believe it is a paraphrase of Jonathan Swift:

From Wikiquote:

http://en.wikiquote.org/wiki/Jonathan_Swift

It is useless to attempt to reason a man out of a thing he was never reasoned into.

• As quoted in Treasury of thought: forming an encyclopædia of quotations from ancient and modern authors (1872) by Maturin Murray Ballou, p. 433.