Although the initial experiments to create life in the laboratory looked promising (with creation of some important organic molecules) little else has been achieved despite all sorts of cocktails of basic compounds and energy sources. It has been argued that life is extremely unlikely to come about accidentally. The chance of accidentally creating a cell has been compared to a hurricane creating a Boeing 747 when it hits a junk yard. The defense is that there are as yet important but unknown self sustaining chains of reactions and other building blocks that provide a path to create the first cell.
But maybe we have no reason to believe that life will happen so easily. Given the idea of the ensemble for a TOE, it is only necessary that SAS's can exist - no matter how improbable. That they exist is of course an empirical fact. An SAS will find the universe is fine tuned in order for that SAS to exist. Presumably this fine tuning can take two forms - in the laws of physics, and in unusual earlier states of the universe. It would appear reasonable for life to be "seeded" if it otherwise would be unlikely to form by accident. Furthermore, Darwinian evolution could be given a "push" in the right direction where it would otherwise have trouble making the necessary jumps. If life indeed is extremely unlikely to form accidentally, then we would have high probability that the only planet supporting life in our universe is the Earth. Presumably there will be an economy of effort in the seeding of life. It is highly unlikely that life will be seeded twice in the same universe. - David