Comment by billytetrud

There are, in fact, reasons to believe that. Nothing definitive of course. But the fact that we haven't been absorbed by a von neumann swarm or something like it places strict limits on the prevalence of life and/or what stages that life can achieve. One would either have to belive that intelligent life is vastly less likely than non-intelligent life, or that life itself is quite rare, or that life simply hasn't been around for much longer than life on earth.