I agree with @srg36 that placebos are very important. The expectation is a very powerful thing. Similar to the example Dr. Simon mentioned in the lecture, sometimes, when people call to make an appointment with a doctor/therapist, they already feel better even before they see the doctor/therapist. Another point I want to point out is that in most cases, the studies also need to be double-blind so both researchers and subject do not know if the subject is taking study med/device or placebo. That way, the study is not bias and the “placebo” wouldn’t create any effect on the result. It also makes the study “cleaner” and makes it easier on the examiner/doctor in case he/she has a connection with a patient (ect) and may unintentionally skew the results. For example: imagine if you are a doctor and your cousin is on a trial, if he or she is on placebo, it’s better if you don’t know because you may tempt to tell him/her, you also may lose your job if you do so. Therefore, in my opinion, placebos are necessary and ethical.