Prejudgments become prejudices only if they are not reversible when exposed to new knowledge.

The mature religious sentiment is ordinarily fashioned in the workshop of doubt.

The dog [in Pavlov's experiments] does not continue to salivate whenever it hears a bell unless sometimes at least an edible offering accompanies the bell. But there are innumerable instances in human life where a single association, never reinforced, results in the establishment of a life-long dynamic system. An experience associated only once with a bereavement, an accident, or a battle, may become the center of a permanent phobia or complex, not in the least dependent on a recurrence of the original shock.

Open-mindedness is considered to be a virtue. But, strictly speaking, it cannot occur. A new experience must be redacted into old categories. We cannot handle each event freshly in its own right. If we did so, of what use would past experience be?

It takes a major unhappiness, a prolonged and bitter experience, to drive us away from loyalties once formed. And sometimes no amount of punishment can make us repudiate our loyalty.

The scientist, by the very nature of his commitment, creates more and more questions, never fewer. Indeed the measure of our intellectual maturity, one philosopher suggests, is our capacity to feel less and less satisfied with our answers to better problems.

Love received and love given comprise the best form of therapy.