I don’t think you can. But if a certain action routinely produces sustained change, that can also be fine. Eg, you can’t blind participants to whether they re

I don’t think you can. But if a certain action routinely produces sustained change, that can also be fine. Eg, you can’t blind participants to whether they receive real therapy or a conversation about the weather, but we’ve concluded that therapy is useful. And you can’t for a similar reason, in that the experience is itself the treatment.