(1) "Sanitation can often be conveyed effectively by information, but morality cannot be conveyed by telling things."
Teaching morals.
It is certainly true that sanitation can be taught by words. That words concerning moral things have no value is a proposition which Dr. Cabot did not clearly and convincingly support.
(2) "People often make sanitary mistakes from ignorance. So far as you are ignorant you cannot be immoral. Morality is conditioned upon knowledge of the right and wrong in question."
Immoral or unmoral.
Of course, one who is ignorant is unmoral and not immoral, but this does not divorce sanitary and moral problems of social disease. An ignorant and unmoral man may have unsanitary sexual habits, but enlighten him regarding venereal disease and his habits make him immoral.
(3) "I cannot see that biology has moral value."
Moral value of biology.
But it may have moral influence just as literature and history and biography may have. Of course, pure biology alone will not make people more sexually moral, but no responsible biologist has ever claimed that it will.
(4) "In morals, we are dealing with the will, and if we believe that the will is guided by intelligence, we must believe that all people who know what is right will do what is right."