It's bad enough to end up dead because we did something stupid; how much more horrible it is to contemplate losing our lives to something unforseeable and unpreventable. There's little defense against an accidental poisoning, a fact we're all too aware of. Moreover, there's even less against a deliberate random poisoning, a fact the 1982 Tylenol murders drove home all too well when seven people died after ingesting a couple of headache tablets.

We want to believe we're masters of our fate, but tales of accidental or deliberate poisoning give lie to that notion. We're vulnerable, and that vulnerability frightens us.