In your world nothing is certain. The computer you're typing on could turn into a tiger and eat you at any moment. The floor beneath your feet could disappear and drop you into hell, there could be a demon in your kitchen, or a flesh-eating zombie in your bathroom.
You can't protect yourself against trows, you don't know anything about them. You believe one thing, someone else believes another. You believe iron will protect you but someone else believes it's only iron in the shape of a horseshoe and who knows what the trow believes. You'd better hope he believes the same thing as you though and not the same thing as that other guy.
Your bit about the theory or relativity is entertaining though - kind of like when Buffy uses an upturned sunbed to toast a vampire.