The logical fallacy in question is called "post hoc, ergo propter hoc," (A, followed in time by B; therefore A caused B) which combines so well in some minds with the exclusivist notion that, since humans are the only sentients we know, humans are the only sentients. However, I don't accept that extending the probability of sentience to non-humans relieves the fallacy.

Thus, even the so-called weak anthropic principle gives me problems, especially when expressed from the fringe where physics and metaphysics are blended into New Age mysticism (cf. Fritjof Capra). As I recall, it takes a clumsy application of the Schroedinger's Cat experiment -- which itself, IMO, is a weak macroworld analogy to illustrate quantum uncertainty -- and concludes therefrom that an interaction must be observed to be complete (otherwise, the probability waves would not collapse, the histories would not sum); therefore, the laws and constants of physics exist particularly to cause the appearance of observers. This strikes me as being just as silly as the "tree falling in the forest" canard. Using my favorite example of a quantum interaction and one possible effect: Do stars shine if there are no eyes to see them?

According to critics, this is simply a tautology, a very elaborate way of saying "if things were different, they would be different", and that this weak anthropic principle is a truism that says nothing and explains nothing because in order for us to be here to ponder the universe, it had to be such that we can exist.