Editor’s note: The following is an excerpt from Reinventing SETI: New Directions in the Search for Extraterrestrial Intelligence, published by Oxford University Press in August 2025. John Gertz is the president and CEO of Zorro Productions, Inc., and a former chairman of the board of the SETI Institute. In his book, Gertz argues that humanity should rethink the search for intelligent life by rejecting outdated paradigms like the Drake Equation, the Fermi Paradox, and the idea of actively broadcasting messages to the stars (a controversial idea known as METI—Messages to Extraterrestrial Intelligence). He argues that instead of expecting alien civilizations to arrive in person, we should prepare for robotic probes that may already be present in our solar system—and start planning for how Earth might respond to first contact. The book presents a new view of the SETI endeavor while offering a roadmap of its future.
It is not at all a given that aliens are far away.
Alien probes might be surveilling us closely right now from within our own solar system, deciding whether to open a channel of communication with Earth or, pursuant to the very poor impressions that they may have already garnered from our nightly news, destroy us forthwith as a wretched species that, if allowed to persist, might eventually become a danger to the whole galaxy. If Judgement Day is in fact well-nigh, our fate may well be in the hands not of a deity, but of algorithms embedded within these robotic probes possessed of artificial intelligence. They may have even less concern or empathy toward us than we have toward cockroaches or weeds.
So, will our first encounter with ET augur our salvation or our destruction? Will ET be benign or hostile? Let’s examine the sum total of hard evidence. Here it is:
Yep, that’s the evidence. Nada. A blank space. No actual evidence whatsoever.
That does not mean that SETI theorists have not taken stances without hard evidence for or against the proposition that ET will be aggressive.
Optimists have argued that alien civilizations will early on in their development acquire the scientific and technical experience to build atomic bombs and other weapons of mass destruction, just as we have. Those civilizations that are inherently aggressive will shortly thereafter self-destruct, leaving only the peaceful civilizations to persist long enough to make contact with the likes of us.
Altruism and kindness are hardwired into all social species. Sociobiologists argue that because our genes strive to pass themselves down through the generations, they will cause their vessels, our bodies, to risk even certain death in order to perpetuate the lives of direct offspring, take large risks for brothers and sisters, take smaller risks in the defense of cousins, and not lift a finger to help a total stranger.
Genes will do whatever it takes to maximize their own replication. Tribalism and nationalism work by tricking the individual into believing that their “brothers in arms” or “motherland” are worth dying for on the basis that shared cultural heritage is equivalent to genetic commonality. Although humans typically feel their tribe or their nation to be one big family, only a rarer few can encompass all of humankind within the boundaries of their altruistic feelings. It takes a saint to broaden love to encompass all living creatures. Maybe ET has passed a boundary whereby it too loves all life in the universe, and perhaps we will only encounter these peaceful alien civilizations.
The law, too, may be on the side of the optimists. As the oldest civilization may be five or more billion years in advance of us, they will have had ample time to discover other coexisting civilizations and devise a body of laws and norms that allow for one and all to peacefully co-inhabit the Milky Way. This imagined galactic code of peaceful coexistence has been called metalaw.
However, pessimism has its own share of arguments as well. ET may be gregarious, social, and altruistic toward members of its own species but still consider other civilizations as vermin. After all, human tribes and nations often behave well internally while also being capable of hating and warring with the “other.” It may be that the galaxy selects for aggressiveness. It would only take one or a few bad actors to displace all of the benign ET civilizations. Leading SETI scientist Seth Shostak has argued that any aliens who would bother to travel to Earth must be, by their very nature, full of initiative and hence must be aggressive. He points to the example of the Incas, who did not meet your average stay-at-home Spaniard but aggressive, gold-hungry Spaniards.
The very fact that the universe is so silent and ET is not obvious may support an argument for pessimism. Perhaps benign alien civilizations are in the majority, but they know something that newbies such as ourselves do not, namely, that the universe is a very dangerous place, and there are some really bad actors out there. They therefore intentionally keep quiet and low profiles, lest they provoke the bad actors.
In this book, I will generally refer to “making a detection” instead of the more common “making contact.” In the first instance, we want to know whether ET exists at all. Obviously, if ET deigns to transmit the Encyclopedia Galactica to us, then we have both detected ET and made contact. But if we detect the presence of ET quite apart from its intention to communicate, say, by observing a large triangularly shaped artificial structure as it passes in front of its star, then that also satisfies our first question: ET does exist.
When can we expect to make our first detection of ET? One of the most prominent SETI scientists, Andrew Siemion, has told me that there is less than a 1% chance of a successful detection, while Seth Shostak relentlessly predicts that ET will definitely, absolutely, and for sure be found soon.
The timeline Shostak has given to various audiences differs a bit (within ten years, within 20 years), but always within his presumed lifetime. I am guessing that he is planning to be around to pop the champagne. Siemion and Shostak will each tell you that he has come to his respective conclusion “by applying a peer-reviewed, quantified, heuristical micro-analysis … blah, blah, blah”—it is a gut-based guess, pure and simple. Both Siemion and Shostak are equally qualified in their field, and both are equally in the dark. It takes real courage to admit that we are clueless.
Which leads to my personal mantra and a main point of this book: Speculate if you cannot resist, but for the love of the heavens, just run the SETI experiment.
But beware the siren call of Copernicus, and pay some heed to that old fool, Aristotle, for it might prove foolish to apply the Copernican Principle to biology in general and to intelligent life in particular. When the Copernican Principle and the Principle of Mediocrity are applied to humanity, they actually fail miserably.
Among Earth’s species, Homo sapiens are anything but mediocre or average. Of all the billions of species that have ever existed on Earth, we are the ones with the largest cranium-to-mass ratio, with the technology to prove the importance of this metric. No other species, living or extinct, comes anywhere close to us.
But before we start crowing, “We’re number one; we’re number one!” we must come to grips with another fact. Of all the technological species in the galaxy, we are almost certainly the very youngest. As it happens, our star is not exactly average at all. Leaving aside the fact that our star is brighter than about 95% of all stars, about 96% of all existing stars are older than our Sun. While our Sun is 4.5 billion years old, the universe as a whole is 13.8 billion years old.
As I noted, allowing for time from star birth to the emergence of a technologically intelligent species, the very first alien civilizations might have arisen more or less 9.3 billion years ago. That’s roughly twice the age of the Earth and constitutes one very large head start on us.
We can barely guess how many civilizations may have arisen since then. However, amongst them all, the chances that any civilization is, like us, in its first 100 years of having the capacity to send and receive radio or laser signals is statistically negligible. So once again, we are nowhere near average, except that in this case we are not reigning champions, but rather, we come in dead last.
That’s right, folks, dead last! Get over it! Among all the alien civilizations in the Milky Way, whatever their number, we are the youngest and least advanced—nothing to crow about.