
On Guard: Defending Your Faith with Reason and Precision (2010), p. 149
Referring to an aphorism of Martin Rees. (see Misattributed below)
Source: The Demon-Haunted World : Science as a Candle in the Dark (1995), Ch. 12 : The Fine Art of Baloney Detection, p. 221
On Guard: Defending Your Faith with Reason and Precision (2010), p. 149
From an appearance in the Discovery Channel program Alien Planet (14 May 2005)
Source: The Journal of Philosophy, Vol. 7, (1910), p. 407
Interview in Speaking of Science Fiction: The Paul Walker Interviews (1978)
Context: When I talk of the purpose of life, I am thinking not only of human life, but of all life on Earth and of the life which must exist upon other planets throughout the universe. It is only of life on Earth, however, that one can speak with any certainty. It seems to me that all life on Earth, the sum total of life upon the Earth, has purpose. If the means were available, we could trace our ancestry — yours and mine — back to the first blob of life-like material that came into being on the planet. The same thing could be done for the spider that spun his web in the grass, and of the grass in which the web was spun, the bird sitting in the tree and the tree in which he sits, the toad waiting for the fly beneath the bush, and for the fly and bush. We are all genetic brothers. The chain of life, tracing back to that primordial day of life's beginning, is unbroken...
Source: Intruders: The Incredible Visitations at Copley Woods (1987), p. 130
Department of Defense news briefing (12 February 2002)
Variant:
Now what is the message there? The message is that there are no "knowns." There are things we know that we know. There are known unknowns. That is to say there are things that we now know we don't know. But there are also unknown unknowns. There are things we do not know we don't know. So when we do the best we can and we pull all this information together, and we then say well that's basically what we see as the situation, that is really only the known knowns and the known unknowns. And each year, we discover a few more of those unknown unknowns.
:It sounds like a riddle. It isn't a riddle. It is a very serious, important matter.
:There's another way to phrase that and that is that the absence of evidence is not evidence of absence. It is basically saying the same thing in a different way. Simply because you do not have evidence that something exists does not mean that you have evidence that it doesn't exist. And yet almost always, when we make our threat assessments, when we look at the world, we end up basing it on the first two pieces of that puzzle, rather than all three.
:* Extending on his earlier comments in a press conference at NATO Headquarters, Brussels, Belgium (6 June 2002) http://www.nato.int/docu/speech/2002/s020606g.htm
2000s