This September, a team of astronomers noticed that the light from a distant star is flickering in a highly irregular pattern. They considered the possibility that comets, debris, and impacts could account for their observations, but each of these explanations was unlikely to varying degrees. What their paper didn’t explore, but they and others are beginning to speculate, is that the flickering might be caused by enormous structures built by an advanced civilization—whether the light might be evidence of ET.

In thinking about this possibility, or other similarly suggestive evidence of extraterrestrial life, an image of an alien creature might come to mind—something green, perhaps, or with tentacles or eye stalks. But in this we are probably mistaken. I would argue that any positive identification of ET will very likely not originate from organic or biological life (as Paul Davies has also argued), but from machines.

Few doubt that machines will gradually surpass more and more of our distinctively human capabilities—or enhance them via cyborg technology. Disagreements are basically about the timescale: the rate of travel, not the direction of travel. The cautious amongst us envisage timescales of centuries rather than decades for these transformations. Be that as it may, the timescales for technological advance are but an instant compared to the timescales of the Darwinian selection that led to humanity’s emergence—and (more relevantly) they are less than a millionth of the vast expanses of time lying ahead. So the outcomes of future technological evolution will surpass humans by as much as we (intellectually) surpass a bug.

There are, after all, chemical and metabolic limits to the size and processing power of “wet” organic brains. Maybe we’re close to these already. It is remarkable that our brains, which have changed little since our ancestors roamed the African Savannah, have allowed us to understand the counter-intuitive worlds of the quantum and the cosmos. But there is no reason to think that our comprehension is matched to an understanding of all key features of reality. Scientific frontiers are advancing fast, but we may sometime “hit the buffers.” There may be phenomena crucial to our long-term destiny that we are not aware of, any more than a monkey comprehends the nature of stars and galaxies.

But no such limits constrain silicon-based computers (still less, perhaps, quantum computers): For these, the potential for further development could be as dramatic as the evolution from mono-cellular organisms to humans. By any definition of “thinking,” the amount and intensity that’s done by organic human-type brains will be utterly swamped by the cerebrations of AI. Abstract thinking by biological brains has underpinned the emergence of all culture and science. But this activity—spanning tens of millennia at most—will be a brief precursor to the more powerful intellects of the inorganic post-human era.