Sure. But then the question becomes, are we really totally surprised without benefit of hindsight? Can we really do no better than to predict that no flying machine will ever be built because no flying machine ever has been? The sin of underconfidence seems relevant here; like, if it’s not a sin to try and do better, we could do a bit better than if we were blind to everything but the reference class.
But the fact that no perpetual motion machine has been built is not the reason we believe the feat to be impossible. We have independent, well-understood reasons for thinking the feat impossible.
But you illustrate my point; it seems possible to discriminate between the probabilities we assign to perpetual motion machines, especially those built from classical wheels and gears without new physics, and flying machines, even without benefit of hindsight.
Indeed, it is obvious that heavier than air flight is possible, because birds fly.
Everyone in the past who has offered a way to “cheat death” has failed miserably. That means that any proposed method has a very low prior probability of being right. There are far more cranks than there are Einsteins and Wright Brothers. The set of “complete unknowns who come out of nowhere and make important contributions” is nearly empty—the Wright Brothers are the only example that I can think of. Even Einstein wasn’t a complete unknown coming from outside the mainstream of physics. Being a patent clerk was his day job. Einstein studied physics in graduate school, and he published many papers in academic journals before he had his Miracle Year. So no, I wouldn’t have believed that the Wright Brothers could make an airplane until they demonstrated that they had one.
And it’s often futile to look at the object-level arguments. It’s not that hard to come up with a good sounding object-level argument for damn near anything, and If you’re not an expert in the relevant field, you can’t even distinguish well-supported facts from blatant lies.
Sure. But then the question becomes, are we really totally surprised without benefit of hindsight? Can we really do no better than to predict that no flying machine will ever be built because no flying machine ever has been? The sin of underconfidence seems relevant here; like, if it’s not a sin to try and do better, we could do a bit better than if we were blind to everything but the reference class.
Can we really do no better than to predict that no perpetual motion machine will ever be built because no perpetual motion machine ever has been?
But the fact that no perpetual motion machine has been built is not the reason we believe the feat to be impossible. We have independent, well-understood reasons for thinking the feat impossible.
As Robin Hanson has pointed out, thermodynamics is not well understood at all.
Conservation of energy is more basic than thermodynamics.
But you illustrate my point; it seems possible to discriminate between the probabilities we assign to perpetual motion machines, especially those built from classical wheels and gears without new physics, and flying machines, even without benefit of hindsight.
Indeed, it is obvious that heavier than air flight is possible, because birds fly.
Everyone in the past who has offered a way to “cheat death” has failed miserably. That means that any proposed method has a very low prior probability of being right. There are far more cranks than there are Einsteins and Wright Brothers. The set of “complete unknowns who come out of nowhere and make important contributions” is nearly empty—the Wright Brothers are the only example that I can think of. Even Einstein wasn’t a complete unknown coming from outside the mainstream of physics. Being a patent clerk was his day job. Einstein studied physics in graduate school, and he published many papers in academic journals before he had his Miracle Year. So no, I wouldn’t have believed that the Wright Brothers could make an airplane until they demonstrated that they had one.
And it’s often futile to look at the object-level arguments. It’s not that hard to come up with a good sounding object-level argument for damn near anything, and If you’re not an expert in the relevant field, you can’t even distinguish well-supported facts from blatant lies.