[mcphage]

> the sentence talks about imaginary pain

It does. But read what the sentence says about "imaginary pain"—that it still hurts. That feeling of hurt is pain. So the sentence is saying that "imaginary pain" is just "pain". So pain that you might think is imaginary, is actually real.

[foldr]

Or, equally, pain that you might think is real is actually imaginary. (If the two terms are equivalent, substitution should work in either direction.) Seems obviously false to me.