“The SETI Institute will not announce the detection of a signal from an extraterrestrial civilization (that is, a signal that is unambiguously non-natural and does not originate from Earth) within the next 20 years.”

Seth Shostak, the senior astronomer for the SETI Institute, famously said "I bet everybody a cup of Starbucks that we’ll find something by 2036." I will offer a slightly more generous timeline, and assert that we will *not* find something by the year 2042. That is, by the year 2042, there will have been no confirmation of the detection of a signal such that the following conditions are met: a) There is an official announcement of positive detection of an unambiguously non-natural, non-Earth signal by The SETI Institute itself. b) There is general consensus among the scientific community (as gauged by the official public statements of reputable scientific organizations) that the signal cannot plausibly be explained by natural phenomena or at least that it is more likely to be artificial than natural. c) Articles in reputable publications (scientific, news media, etc) announce the detection of the signal and characterize it as "first contact" or "a signal from ET," etc. The reason that this will not happen is because either extraterrestrial technological civilizations do not exist, or if they do, they are so extremely far away that we are for all intents and purposes alone, or they do exist close enough to see direct light from the Earth, but don't care to communicate with us. I believe that Sandberg, Drexler, and Ord argue convincingly that we should not expect to find evidence of intelligent life beyond Earth. The timescales involved in critical, contingent events leading to the evolution of complex, intelligent organisms suggests that human-like intelligence is likely to be so rare that we may represent the only time it has so far come about in the observable universe. https://arxiv.org/abs/1806.02404 But to see why the premise of SETI is logically flawed (and deeply anthropocentric) in and of itself, let's assume it is correct and see what it logically entails: That is, there is at least one extraterrestrial civilization capable of beaming an electromagnetic signal at Earth, and it is doing so right now (we have only to sift through the spectrum of frequencies and look in the right place to find it). 1) Such a civilization must differ in age from ours on the order of millions if not hundreds of millions of years (any less would be the equivalent of bumping into a random person on the street and finding out you were born within less than e.g. a day of each other). So their civilization is at the very least 1 million years older than ours. 2) Such a civilization has a direct, unobstructed line of sight to Earth (eg not obstructed by the central galactic bulge, or a nebula, or whatever), otherwise a signal would not be beamed toward Earth in the first place. 3) Such a civilization has or has had astronomy, otherwise they would not have detected Earth in the first place. We are on the verge of being able to detect indirect evidence for the existence of life on other worlds by analyzing their atmospheres for biogenic properties. Possibly we will be able to do this with the JWST and other technologies in the very near-term future. The Earth has been broadcasting such a biosignature since the Great Oxidation Event ~2 billion years ago; if this was ambiguous, then the Earth's atmospheric concentration of oxygen went up even higher just over 500 million years ago. Any alien astronomers would not have failed to detect this biosignature in Earth's atmosphere, and with millions (or hundreds of millions) of years technological advance, it is implausible that they would not have understood what this means in terms of the existence of life on Earth. This would make Earth very special indeed if complex life like ours is not abundant throughout the galaxy. So this alien civilization has known for millions of years that Earth hosts life, and according to SETI, they desire to communicate with Earth's potentially intelligent inhabitants. But this same civilization has had *millions* of years to analyze Earth in as much detail as they wish; even a sub-light probe could make a roundtrip in this amount of time. No doubt they have more advanced imaging, computing (for simulations, etc). Again, this is a difference on the order of a million years or more of technological advance. They've had as much time to figure out how to unambiguously make their presence known to the inhabitants of Earth. This is why SETI as a concept is fundamentally anthropocentric; it assumes that the burden of communication falls mostly on *us* in that all ET has to do is the send the signal, but we have to identify and presumably decipher it. This would be as bizarre as if we were isolated hunter-gatherers waiting for a smoke signal from people using helicopters and airplanes; if the more technologically advanced people wanted to unambiguously communicate, it would be utterly trivial for them to do so whether the isolated hunter-gatherers are looking for smoke signals or not (indeed, this has happened many times throughout history). Ultimately, ET has been aware of the existence of life on Earth for potentially *hundreds of millions of years* and have had at least as long to figure out how to communicate with us if they wanted to. The fact that their existence or any message they had for us is not already unambiguously known and obvious is implausible. In fact, the notion that after millions of years of being able to study Earth in as much exhaustive detail as they wished, they've decided that they *do* want to communicate but that they'll leave it for us to find their signal like a needle in a haystack...is absurd. I would very much love to lose this bet, but I suspect that in 20 years we'll all be drinking coffee and *not* talking about a signal from ET.