Hello, a couple decades ago, an argument was introduced in a notable physics journal of some kind, but I cannot recall the name of this argument, or the journal. I believe it might have been associated with Cambridge, but can't remember. The argument is a logical theory as to why the likelihood of ET life is very close to zero. I am wondering if anyone can help me remember the author/title/journal of this argument. This is as much a summary of the argument as I recall -- and I am seeking more details provided in the original article: The idea is that if *intelligent* life were possible elsewhere in the galaxy, then we'd have been aware of it a long time ago. That intelligent life would really only have to succeed on one other occasion to propagate throughout the galaxy by this present point in time. That the speed with which our own human life sprung up was so quick, that if it were easily developed elsewhere in the universe, it would have had many opportunities in the distant past to do so, of which at least one other species would have succeeded by now if it were possible. That it has not, or that we are not aware of any, suggests that either it has never happened, or has happened in a way in which we will never be aware. And that therefore our understanding of ET life is not likely to ever change. It is a relatively well-known argument against alien life, well-known primarily among well-read physicists and serious academics. If anyone can recall the source of this argument, I'd like to know and read the original article. Thanks.