[perl4ever]

There is no way to coherently define the "placebo effect".

When you test a treatment vs. placebo, and speculate that there is a "placebo effect", it means that you are supposing that lying about treatment produces a therapeutic effect.

But you can't test a placebo vs. nothing, because a placebo is not a treatment, and nothing is not a placebo.

Giving a sugar pill and disclosing you are giving a sugar pill is not the same thing as lying about treatment (unless the recipient believes it is efficacious). Lying about it being efficacious doesn't help your experiment unless it's a credible lie.

Giving "nothing" cannot be a control because it is obviously different from a sugar pill. So you cannot do a blind test.

The idea of testing a placebo effect is an epistemological morass.