When attempting to introduce non-rationalists to the ideas of cryonics or Strong AI, it appears that their primary objections tend to be rooted in the absurdity heuristic. They don't believe they inhabit a universe where such weird technologies could actually work. To deal with this, I thought it would be useful to have a cache of examples of technologies that have actually been implemented that did, or ideally, still do, challenge our intuitions about the way the universe works.
The first example that comes to my mind is computers in general; imagine what Ernest Rutherford, let alone Benjamin Franklin, would have thought of a machine that uses electricity to calculate, and do those calculations so fast that they can express nearly anything as calculations. Nothing we know about how the universe works says it shouldn't be possible, indeed it obviously is knowing what we do now, but imagine how weird this would have seemed back when we were just coming to grips with how electricity actually worked.
I suspect there may be better examples to challenge the intuitions of people who've grown up in an age where computers are commonplace though. So does anyone have any to volunteer?
Public-key encryption is very weird; most cryptographers did not believe it was possible before it was done. But anyone who understands public-key encryption enough to appreciate this point is probably not in your target non-rationalist audience.
I've found that most people who are initially dubious of the idea of public key encryption will at least agree that it is plausible once you demonstrate the asymmetry of inverse operations like multiplying primes / factorising products.
Once you convince them that it's easy to multiply primes but hard to factorise products, you can say "there is an algorithm where you can encrypt a message using the product, but to decrypt it you need the original primes" and (in my experience) they will usually find this sufficiently plausible to overcome the in... (read more)