Well, no. Amino acids seem to happen no matter what they try in the lab. Nucleotides have happened many times, starting in the '60s, as have polypeptides. Compl

Well, no. Amino acids seem to happen no matter what they try in the lab. Nucleotides have happened many times, starting in the '60s, as have polypeptides. Complex organics are nearly inevitable. There have even been RNA oligomers formed on a mineral substrate under conditions that probably existed in the Hadean[1] - so basically lab-grown prebiotics. An awful lot has happened since the Miller-Urey experiment. That doesn't mean that life as we define it is inevitable, or that it will survive all of the various attempts the Universe makes at eliminating it, what with all of the huge rocks and snowballs being thrown around and oozing and exploding lava and such. The most basic building blacks just happen. The minor assemblies seem to be easy. The smallest key pieces seem to involve a bit of luck in the beginning - it may take a handy bit of inorganic scaffolding, some weather and something like tides to build the first self-replicators, but one you have them, the scaffolding isn't needed anymore. Getting from there to proper cells - replicating, metabolizing and homeostatic - takes a considerably bigger collection of chance meetings of chemistry and environment, which may take just a bit longer than we've been trying so far, and a much bigger lab. Even if replicators are common, "real" life might not be. And then there was a little more than a three-billion-year wait for cells to stay stuck together and cooperating in the only successful experiment we know of. Multicellular life may be rare, even if life is common. Tool-using, highly intelligent life that has harnessed fire to its will doesn't necessarily follow, and that's pretty much a sine qua non of a civilisation capable of interstellar communication, let alone interstellar travel. No matter how easy the first 500 million years or so of the formation of life on Earth may be, the assumption that what happened over the next 4 billion years is somehow a straight shot is one hell of an assumption. Almost nothing happened for about three billion of those years, and the catalyst for multicellularity may have been an exceedingly rare, even unique, set of circumstances. The universe, the galaxy, may indeed be teeming with life, but it's much, much more likely to be little green slime-covered mud mounds than little green men. [1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1664692/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1664692/