The seemingly insuperable difficulties of deep-space travel suggest an intention to keep us fixed at home in our own solar system, and the physical nature of our part of the Universe, as well as the basic rules of physics and chemistry, have a warning look about them, like barriers designed to isolate intelligent life. This means that for us, unlike the situation for humble microorganisms, deep-space travel is probably a stark impossibility.

Words are like harpoons. Once they go in, they are very hard to pull out.

It is emphatically the case that life could not arise spontaneously in a primeval soup of any kind.... Furthermore, no geological evidence indicates an organic soup ever existed on this planet. We may therefore with fairness call this scenario the myth of the pre-biotic soup.

It is a mistake to imagine that potentially great men are rare. It is the conditions that permit the promise of greatness to be fulfilled that are rare. What is so difficult to achieve is the cultural background that permits potential greatness to be converted into actual greatness.

It is in the world of ideas and in the relation of his brain to the universe itself that the superiority of Man lies. The rise of Man may justly be described as an adventure in ideas.

Once a photograph of the Earth, taken from outside, is available, we shall, in an emotional sense, acquire an additional dimension.

The suggestion that petroleum might have arisen from some transformation of squashed fish or biological detritus is surely the silliest notion to have been entertained by substantial numbers of persons over an extended period of time.