I've been wondering why science took so long to appear. Why didn't China, which invented so many other things in the first millennial, just keep on going and invent science by 1000 AD? For that matter why didn't the Greeks invent the scientific method during their heyday? What were they missing?
As Carl Sagan declares in his book (and TV series) "Cosmos" : "Writings about fossils, gems, earthquakes, and volcanoes date back to the Greeks, more than 2300 years ago. Certainly, the most influential Greek philosopher was Aristotle. Unfortunately, Aristotle's explanations of the natural world were not derived from keen observations and experiments, as in modern science. Instead, they were arbitrary pronouncements based on the limited knowledge of his day."
But they could have been, even back then. Aristotle appears to have lacked no materials which would have prevented him from doing simple experiments and observations. There were many things he could not see without telescope and microscope, but there is still hundreds, thousands, if not millions of things he could have measured with tools he did have. But he did not because he didn't have the mindset.
We know that if a modern scientist today were sent back in time 2,300 years to the early Greek city states he or she could easily gather measurable data, and set up experiments with controls. In fact in the BBC produced a cool reality show called Rough Science that deposited scientists onto an island and had them create modern instruments such a telephone, phonograph, radio, etc., using materials found on the island. To make this crude anachronistic versions of modern technology the experts had to employ the scientific method with primitive tools. In some cases, their tools and materials were no better than what a wealthy Greek philosopher might have been able to get hold of in 300 BC.
It's not just simple things. Danny Hillis made a computer out of tinkertoys, a computer that the Greeks could have built, if they had thought of it. It would have been of no use to them, but the Greeks often dabbled in "useless" mathematical and philosophical knowledge. There are thousands of sophisticated technologies the Greeks could have produced with their tools, but did not because the tech was too many steps removed from everything else they were doing.
Hard science fiction author Greg Egan believes that even the theory of relativity could be deduced by a pre-industrial society, a case he makes in his new novel, Incandescence. As he says on his website (edited here):
"Incandescence" grew out of the notion that the theory of general relativity - widely regarded as one of the pinnacles of human intellectual achievement - could be discovered by a pre-industrial civilization with no steam engines, no electric lights, no radio transmitters, and absolutely no tradition of astronomy.
At first glance, this premise might strike you as a little hard to believe. We humans came to a detailed understanding of gravity after centuries of painstaking astronomical observations, most crucially of the motions of the planets across the sky...
How, then, could my alien civilization possibly reach the same conceptual heights, when they were armed with none of these apparent prerequisites? The short answer is that they would need to be living in just the right environment: the accretion disk of a large black hole... My aliens would probably need to be sheltering deep inside some rocky structure to protect them from the radiation of the accretion disk - and the glow of the disk itself would also render astronomy immensely difficult.
Blind to the heavens, how could they come to learn anything at all about gravity, let alone the subtleties of general relativity? After all, didn't Einstein tell us that if we're free-falling, weightless, in a windowless elevator, gravity itself becomes impossible to detect?
Not quite! To render its passenger completely oblivious to gravity, not only does the elevator need to be small, but the passenger's observations need to be curtailed in time just as surely as they're limited in space. Given time, gravity makes its mark. Forget about black holes for a moment: even inside a windowless space station orbiting the Earth, you could easily prove that you were not just drifting through interstellar space, light-years from the nearest planet. How? Put on your space suit, and pump out all the station's air. Then fill the station with small objects - paper clips, pens, whatever - being careful to place them initially at rest with respect to the walls.
Wait, and see what happens.
Most objects will eventually hit the walls; the exact proportion will depend on the station's spin. But however the station is or isn't spinning, some objects will undergo a cyclic motion, moving back and forth, all with the same period.
That period is the orbital period of the space station around the Earth. The paper clips and pens that are moving back and forth inside the station are following orbits that are inclined at a very small angle to the orbit of the station's center of mass. Twice in every orbit, the two paths cross, and the paper clip passes through the center of the space station. Then it moves away, reaches the point of greatest separation of the orbits, then turns around and comes back.
This minuscule difference in orbits is enough to reveal the fact that you're not drifting in interstellar space. A sufficiently delicate spring balance could reveal the tiny "tidal gravitational force" that is another way of thinking about exactly the same thing, but unless the orbital period was very long, you could stick with the technology-free approach and just watch and wait.
A range of simple experiments like this - none of them much harder than those conducted by Galileo and his contemporaries - were the solution to my aliens' need to catch up with Newton. But catching up with Einstein? Surely that was beyond hope?
I thought it might be, until I sat down and did some detailed calculations. It turned out that, close to a black hole, the differences between Newton's and Einstein's predictions would easily be big enough for anyone to spot without sophisticated instrumentation.
What about sophisticated mathematics? The geometry of general relativity isn't trivial, but much of its difficulty, for us, revolves around the need to dispose of our preconceptions. By putting my aliens in a world of curved and twisted tunnels, rather than the flat, almost Euclidean landscape of a patch of planetary surface, they came better prepared for the need to cope with a space-time geometry that also twisted and curved.
The result was an alternative, low-tech path into some of the most beautiful truths we've yet discovered about the universe.
If anachronistic science occurs in the past, then by definition there must be future technology that we are capable of creating today, if only we knew how. For instance, I have a public Long Bet prediction that in 2075 some smart high school kids will be able to cobble together a working artificial intelligence from vintage 2005 hardware unearthed in landfills. Using only materials that we have today, and a lot of new software, a perfectly good AI could be made. If true, that means that in theory we could make an AI today with the chips and hardware we already have. We are just missing the know-how to hook them up.
Similarly, we might be able to make an anti-gravity machine with the materials and technology we have today, if only we knew how. The major problem is that we don't know what technologies can be time shifted (and we know almost nothing about gravity). But we can be sure by simple statistics that some technologies can be shifted. It's amazing how powerful "knowing that it can work" can be. It's worth at least 100 IQ points.
Imagine that in possibility space of knowledge the point "Greek logic" sits directly adjacent to "Greek computation," but separated by a deep chasm. Only a small set of knowledge separates them, but that short distance in knowledge took 20 centuries to cross. Perhaps it is the same today with "2005 hardware" and "2005 AI." Ordinarily there is no way to transverse that gap. But I wonder if there are techniques which would allow us to scientifically tunnel through to those adjacent places, where all that is separating the positions is "knowing it can work"?