Why We Haven’t Met Any Aliens
A terrible article. So let's say something more interesting. There are several important ideas intertwined together around the Fermi Paradox:<p>1) Fermi Paradox<p>Why haven't we seen any evidence in the observable universe of megascale activities and exponential growth comparable to those that we know that our descendants will be capable of, and fairly soon?<p><a href="http://en.wikipedia.org/wiki/Fermi_paradox" rel="nofollow">http://en.wikipedia.org/wiki/Fermi_paradox</a><p>2) The Outer Bounds of the Possible<p>Can we convert our entire future light cone into computronium? There seems to be no physical laws to prevent that outcome, and absent being stopped soon, the tiny fraction of our machine descendants to go all out for self-replication and expansion will set this program in motion.<p>3) The Great Filter<p>Assuming we're in base reality and everything out there is running much as our present physics understands it to run, are we past the barrier that stops intelligences from converting the observable universe into computronium? Or not?<p><a href="http://en.wikipedia.org/wiki/Great_Filter" rel="nofollow">http://en.wikipedia.org/wiki/Great_Filter</a><p>4) The Simulation Argument<p>Or are we simulations, alone in our virtual machine?<p><a href="http://en.wikipedia.org/wiki/Simulation_hypothesis" rel="nofollow">http://en.wikipedia.org/wiki/Simulation_hypothesis</a><p>----<p>All these are linked via this rather depressing line of thought:<p>"A technologically mature “posthuman” civilization would have enormous computing power. Based on this empirical fact, the simulation argument shows that at least one of the following propositions is true:<p>- The fraction of human-level civilizations that reach a posthuman stage is very close to zero;<p>- The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero;<p>- The fraction of all people with our kind of experiences that are living in a simulation is very close to one.<p>If (1) is true, then we will almost certainly go extinct before reaching posthumanity. If (2) is true, then there must be a strong convergence among the courses of advanced civilizations so that virtually none contains any relatively wealthy individuals who desire to run ancestor-simulations and are free to do so. If (3) is true, then we almost certainly live in a simulation. In the dark forest of our current ignorance, it seems sensible to apportion one’s credence roughly evenly between (1), (2), and (3).<p>Unless we are now living in a simulation, our descendants will almost certainly never run an ancestor-simulation."<p>----<p>The bottom line is that there appears to be a large gap in our understanding of the evolution of intelligence in the universe. By all counts, our galaxy should have many civilizations across its span, and by all counts if they're anything like us, their most aggressive descendant factions will turn the whole galaxy into computronium in a few tens of millions of years. But we don't see even the first glimmers of any such thing.