Seti@home

I don't think your position is that cut and dried. The Drake equation has so many variables that are unknown that we can't do any predicting based on it. We have shown from observation that Jupiter size planets are common but we know nothing yet about the percentage of Earthlike planets, what type of life is possible nor do we have any idea of how often life should arise on Earthlike planets if there are any. Stars can be quite variable over their lifetime and a world such as ours may be a result of highly unusual conditions that are not common at all. I am afraid it is going to be many more decades before we will be able to speak with any authority on what the odds of intelligent life are. All we can say so far is that we have yet to find anything else.

On the contrary ... it is most certainly "cut and dried" in the sense given. The proponents of Seti are trapped in a logical contradiction from which they cannot extricate themselves by any means ... one of their most fundamental assumptions must be false.

Note: Assumptions are not proven facts so we don't need any data to back them up. Their assumptions are contradictory.

by their actions they are saying that ...

There is somebody out there.
They exist in some numbers.

To hold this view ... given the age of the galaxy (which they would all agree to) ... and the mathematical facts of colonization (which they must agree to) ... they must hold the belief that: either there is no one there in quantity (in which case they should not be funded) ... or ... interplanetary travel is impossible. But they don't profess either view as a consensus. Rather they exist in a contradictory state hoping that no one will notice and thus they should continue to be funded ;o)

I don't buy the argument that we would have been colonized or discovered several times, that depends on a whole host of information that we either do not have or have extremely bad data. I can agree that SETI is dependant upon detecting communication of the radio-wave type that our civilization is capable of emitting and that any such civilization is going to have to be relatively near to us to have a chance of finding them. But what does it tell us? There could be a civilization more advanced that is using communication that we are incapable of detecting or they could be at the hunter-gatherer stage. SETI can't really tell us much at all unless it does succeed in finding an intelligent signal. Non observation doesn't mean life isn't there but it certainly isn't good PR for funding. That is one of the interesting things about SETI in that non-observation doesn't invalidate it because you can always set the distance to the nearest civilization farther and farther away.