Personally, I'm inclined to say SETI meets all the criteria of science, only on a very long timescale. In principle, the question of whether there is other intelligent life in this galaxy can be answered in the positive or negative, but given that it's 30,000 light years or so to galactic central point, and at least that again to the far side of the galaxy, it's a question that's likely to take millennia to answer.
Similarly, I would be hesitant to dismiss the
Drake Equation (N = R* • fp • ne • fl • fi • fc • L) as a mere "intellectual exercise." True, the values of most of its factors are,
at present, unknown, and as a result the value of
N is also unknown, but that doesn't mean they are
unknowable. Just a couple of weeks ago, Margaret Turnbull of the Carnegie Institution held a presentation to the American Assocation for the Advancement of Science outlining how she'd gone through the catalogue of the 120,000 stars closest to Earth and eliminated those which lacked the potential to be habitable, leaving 17,000 "habstars." This kind of work brings us closer to identifying a value which may be applied to the [R* • fp • ne] part of the Drake Equation. As we learn more about the galaxy, values may be assigned to other factors as well until, finally,
N becomes known. But again, this will take a long time; definitely beyond the lifetime of anyone currently on this board, I'd wager, and more likely in the order of centuries. Hell, in astronomic terms, we've only been at this business for the blink of an eye. I assume that
scribble's no longer around, but this challenge requires a response:
Just as an exercise, I'd like anyone to try to give me a number - any number - for how likely it is that we will find life elsewhere.
I'd say the answer is 1, provided you don't attach a time limit (as the original challenge did not), and you interpret "we" to mean humanity in general. If you want my opinion how likely humanity is to find extraterrestrial life in our lifetimes, the answer is 0.
The underlying point here is that it's not written anywhere in the rules of the scientific method that a hypothesis has to be testable
within a certain amount of time. As I say, SETI is unlikely to provide an answer one way or another on the existence of extraterrestial life anytime soon, but in principle, an answer
can be found. By contrast, religious doctrines, for example, defy testing entirely as a matter of principle. Speaking of the paranormal...
For those people that have voted Science, how is SETI different from searches for 'psi' stuff [...] ?
First, we do not yet possess the ability to physically check out other "habstars" to ascertain whether or not they harbor intelligent life. By contrast, we've had hundreds of years to examine the existence of "psi" ability here on Earth, and we've come up empty-handed so far. Fermi's Paradox can readily be adapted to "psi" ability, and much more persuasively than it can to extraterrestrial life; namely, if "psi" ability is real, why has nobody managed to claim the JREF Million yet?
Second, and more importantly, the potential existence of extraterrestrial life does not contravene any of the hitherto identified laws of physics (indeed, the "known" laws of physics arguably point to the likelihood of intelligent life outside our solar system), whereas "psi" abilities do.
My objection to SETI is that it assumes a communications paradigm that even we are not going to cling to much longer: broadcast analog transmissions. Right here on Earth, we are rapidly switching from broadcasting to point-to-point data transfer (if the aliens are all using cable TV, we'll never spot them).
Hardly. Certain applications will continue to require broadcast transmission for the foreseeable future; armed forces and aviation (both military and civilian) will continue to use broadcast electro-magnetic emissions, in communications and in radar. GPS satellites have to broadcast their positions to be of use to ground systems. Satellite radio not only continues to rely on broadcast methods, but actually puts the transmitter in orbit.
What SETI is after, ultimately, is not "radio broadcasts" in the more limited sense, but electro-magnetic emissions which display a degree of ordering which can only be artificial. The argument "but what if the aliens don't use radio like we do?" doesn't hold water. The known laws of physics limit the options for wireless communication to some kind of electro-magnetic emissions, since visible light (e.g. laser) doesn't go around curves and telepathy contravenes the laws of physics.
. I've spent the last few years working on models of how searches take place, tossing in different parameters, and seeing what happens.
