| "Maybe people intuitively figured out what was up (one of the parameters of the Drake Equation must be much lower than our estimate) but stopped there and didn’t bother explaining the formal probability argument." There's no "intuitively" about it. We know from the data available that the probability of machine-building general intelligence of the kind that is unique to humans on Earth is fantastically unlikely to arise. It depends on a confluence of completely unrelated selective pressures: one on tool-making, one on social cooperation, and one on continuous mate competition/selection. There is good evidence that all of those forces are important to specifically human--not dolphin or bird or whatever--intelligence on Earth, and without any one of them we'd still be fairly handy monkey-creatures banging rocks around. As well as a theoretical understanding, we have empirical data. We can ask, "If something is at all probable how many times will it have evolved on Earth?" Eyes, for example, have evolved independently multiple times, based on differences in retinal biochemistry. Wings and fins and legs have also evolved many times across an incredible diversity of species. This tells us that things that are easy to evolve have evolved multiple times in Earth's history. Specifically human, machine-building intelligence has evolved exactly once. This is strong evidence that it has an enormously low probability. Once you've realized that one of the parameters in the Drake equation is incredibly small, the Silent Universe is no longer surprising. And both empirically and theoretically, the probability of evolving specifically human, machine-building intelligence is incredibly small. However, I have never met anyone enamoured of Fermi's Paradox who gives any credence to this, which is why no attempt to resolve the paradox will ever have any effect on the discussion. This is in general the case with so-called paradoxes: no matter how many times they are clearly and simply resolved, people who want there to be paradoxes will pretend the resolution doesn't exist, or will deliberately misrepresent it as a non-solution. Or they will present some other non-solution as more compelling, even when the solution presented makes those non-solutions unnecessary. |