One of those bits of advice

Science Friday has a bit on with Oliver Sacks that includes some advice on distinguishing hallucinations. For example, he says, if you see a sky-blue cow up in the air, that's a hallucination.

And that reminds me of an old piece of advice (which I know I've shared with several of you):

When you are tripping, all cars are real. If you see a purple car with pink polka-dots on it coming at you out of the sky, get out of the way. You might be hallucinating the sky.

I believe I first heard this from someone at Senior House, but darned if I can remember who it was.