If we will only allow that, as we progress, we remain unsure, we will leave opportunities for alternatives.

Scientific knowledge is an enabling power to do either good or bad — but it does not carry instructions on how to use it.

So my antagonist said, "Is it impossible that there are flying saucers? Can you prove that it's impossible?" "No," I said, "I can't prove it's impossible. It's just very unlikely." At that he said, "You are very unscientific. If you can't prove it impossible then how can you say that it's unlikely?" But that is the way that is scientific. It is scientific only to say what is more likely and what less likely, and not to be proving all the time the possible and impossible.

If the professors of English will complain to me that the students who come to the universities, after all those years of study, still cannot spell 'friend,' I say to them that something's the matter with the way you spell friend.

There are thousands of years in the past, and there is an unknown amount of time in the future. There are all kinds of opportunities, and there are all kinds of dangers.

There is no harm in doubt and skepticism, for it is through these that new discoveries are made.

There is a computer disease that anybody who works with computers knows about. It's a very serious disease and it interferes completely with the work. The trouble with computers is that you 'play' with them!