Measures of sterilization should, in my opinion, be very definitely confined to persons who are mentally defective

Do not fear to be eccentric in opinion, for every opinion now accepted was once eccentric.

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widely spread belief is more likely to be foolish than sensible.

One should respect public opinion insofar as is necessary to avoid starvation and keep out of prison, but anything that goes beyond this is voluntary submission to an unnecessary tyranny.

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd.

A process which led from the amoeba to man appeared to the philosophers to be obviously a progress though whether the amoeba would agree with this opinion is not known.