It is often by a trivial, even an anecdotal decision, that we direct our activities into a certain channel, and thus determine which of the potential expressions of our individuality become manifest. Usually we know nothing of the ultimate orientation or of the outlet toward which we travel, and the stream sweeps us to a formula of life from which there is no returning. Every decision is like a murder, and our march forward is over the stillborn bodies of all our possible selves that will never be.

Sometimes the more measurable drives out the most important.

Human destiny is bound to remain a gamble, because at some unpredictable time and in some unforeseeable manner nature will strike back.

Eradication of microbial disease is a will-o'-the-wisp; pursuing it leads into a morass of hazy biological concepts and half truths.

Any attempt to shape the world and modify human personality in order to create a self-chosen pattern of life involves many unknown consequences. Human destiny is bound to remain a gamble, because at some unpredictable time and in some unforeseeable manner nature will strike back. The multiplicity of determinants which affect biological systems limits the power of the experimental method to predict their trends and behavior.

Men are naturally most impressed by diseases which have obvious manifestations, yet some of their worst enemies creep on them unobtrusively.

As long as mankind is made up of independent individuals with free will, there cannot be any social status quo. Men will develop new urges, and these will give rise to new problems, which will require ever new solutions. Human life implies adventure, and there is no adventure without struggles and dangers.