I’m working on my keynote talk for next week’s Sustainable Cosmetics Summit, and I got to thinking about the paradigm shifts in science that are changing the business of beauty. To sum it up: We didn’t used to know what we know now about the health risks posed by toxic chemicals. So, now that we know, what are we going to do about it? We know, for example, that chemicals don’t act in the predictable ways once assumed. You’ve probably heard the old adage “the dose makes the poison” — the idea coined by Paracelsus in the 1500s (and oft repeated by beauty industry execs) that toxic substances are harmless in small enough doses, while harmless substances can be deadly if over-consumed.