So I went to see Neil deGrasse Tyson last night at UB. He spoke for about 2 hours, doing his normal talk about basic physics and astronomy, then did a pretty long Q&A afterwards.
The talk didn’t really have new information, but it was cool to see in person. I got to ask a question about SETI but I don’t think I phrased it quite right. It was about whether or not what they were doing was falsifiable and if not, whether that made it unscientific. He answered by giving what seemed like a prepared response for questions about SETI in general, which was all very interesting and all, but didn’t really get to my point.
At first he made an analogy to searching for life in the ocean by studying it little by little. That’s basically what SETI does for possible radio signals from the closest stars. And then after finding no results, you can continue searching. So it was like he was framing the SETI hypothesis as a set of smaller hypotheses. He was talking about falsifying a hypothesis like “Is there a radio signal in X direction at Y frequency?” which can be easily falsified or verified by direct observation while I meant the larger hypothesis of “Does intelligent life exist on other worlds?” which I don’t think really can be falsified.
And that’s I think where his analogy fell apart because the ocean – global warming aside – is not expanding. It’s finite, and we have a pretty good idea of where it begins and ends in a practical, day-by-day sense. At least it’s not expanding at an accelerating rate which can continue for trillions of years, like the Universe.
So if the truth of our situation is that Earth really is the only place where intelligent life evolved (which is possible), we couldn’t really know for sure because by the time we’ve accumulated all the data and analyzed it, the Universe has already expanded by a lot, revealing even more possible places to search for intelligent life. It could be that what he was getting at was that maybe someday we could have technology that could really act that quickly, but I don’t see how that could be possible given the limitations on things like the speed of light and that sort of thing.
UPDATE: Here is a short clip UB posted on the YouTube: