Ignorance. The true effect, at present, of placebo effect on science is ignorance. Ignorance of cause, ignorance of consequences.
I am talking about the actual impact of placebo effect on science, and doing so in the hope that someday we can change that effect to something as powerful and useful as placebo effect actually is.
First, we need to clearly define some terms. I'll use Webster's. It's a a good place to start. Placebo effects don't “work”. We know that placebos work. But the question is about placebo effects, not placebos.