Reply when questioned on the safety of the polio vaccine he developed: It is safe, and you can't get safer than safe. - Jonas Salk

Some people are constructive, if you like. Others are destructive. It's this diversity in humankind that results in some making positive contributions and some negative contributions. It's necessary to have enough to make positive contributions to overcome the problems of each age.

Since whatever we do has to be part of a team, part of a community, we have to attempt to bring together those who have the same conviction, see the same things. Then it becomes a matter of time, when one or the other will prevail. Fortunately, there is all this diversity, and if not for that, problems would not be solved.

Risks, I like to say, always pay off. You learn what to do, or what not to do.