One interesting notion that strikes me from time to time, like now, is that if String Theory [ M Theory] is correct or nearly so, the greatly anticipated theory of everything, or TOE, is not a theory of science and never can be. Rather, M theory stands as a philosophical proposition, and it appears tha tthis will always be true. As far as we know, M Theory can never be tested or qualify as a theory of science. So, this makes me wonder if this might be implicitly required somehow; perhaps due to a philosophical limitation built into science that we've missed? Anyway, not to be taken too seriously, it's just a thought that I have now and again.