To transmit or not to transmit?
Earth’s radio leakage and deliberate transmissions will likely be identifiable by ETI as a technological signature because no other examples of such signals exist in nature. The ability of ETI to decipher or interpret the content of a signal is therefore irrelevant to their ability to use it to learn that humans exist...
To transmit or not to transmit
[B]ecause we cannot estimate the probability or magnitude of contact with ETI, we make no attempt to calculate the term. By extension, any conclusions that depend on knowing are conditional.
David Brin wrote this to me in a follow-up email:
The authors' arguments boil down to excusing METI via what is known as the "barn door argument -- the notion that Earth civilization is already drawing attention to itself (the horses are already out) so why bother restricting anyone from shouting into the cosmos (don't bother closing the barn door once the horses are gone.) It is both specious and manipulatively hypocritical on several levels.
1) The paper is flawed because it does not even discuss the dwell or integration time that an alien square kilometer array (SKA) must dedicate, staring solely at Earth for an extended period, in order to pick out signal from noise. If that time is long, and most scholars think so, then no civilization will do it unless they already suspect there is something or someone here! That is, unless they have gobs and gobs of SKAs to play with. Both of those are possible, for varied reasons. But they aren't super-likely.
2) It is disingenuous to imply that METI beams -- e.g. Zaitsev's from Evpatoria -- are just like the radars used by the USAF to characterize orbital debris. I'd like to see Dr. Busch and his colleagues defend that implication. Narrow, coherent, laser-like and powerful, beams like the ones used by Zaitsev to do his cosmic shouting are like a lighthouse next to a flashlight.
3) The Barn Door excuse takes "disingenuous" to a level that tips over into outright sophistry and deceit. Let us ask, if aliens already detect us, why are some fetishists so eager to blast away "yoo-hoo" shouts into space? They aim to accomplish a major and dramatic change in the visibility of Earth civilization... they say so publicly. Hence, the Barn Door excuse is a travesty of verbal legerdemain.
Busch & company then dive into the worst part of the paper, a razzle-dazzle arm-waving of "risk factors" that bear no relationship to the way the science of risk analysis operates, conjuring inputs out of thin air and then declaring or "positing" that the likely good outweighs any calculation of possible bad outcomes. This exercise was too grimly awful to even be amusing, especially since the "dissidents" in the SETI community, including John Billingham, Michael Michaud and myself, have not asked for a ban on transmissions from Earth, only widespread and eclectic collegial discussion of this issue, with inputs by experts who actually know about the many and varied risk factors involved.
Reiterating, the thing we have asked for is a wider discussion, beyond the insular community of SETI fans and a few dozen radio astronomers, of a matter that could have great bearing on the success - and even survival - of our descendants. We seek a vast and fascinating exchange, bringing together the planet's best minds to enthrall the public with open deliberation of all factors. Those who refuse such discussion - shrugging aside any need or moral obligation to consult the rest of us - are the ones practicing censorship. They are the ones engaging in reckless assumptions, willing to wager our posterity on a few "posits" on the back of an envelope.