The CUSP

This is copy/pasted from my comments on facebook. Here being probably more appropriate and in case anyone wishes to pull me up on something.

I have to take a few exceptions to a couple of things in this weeks show. I'll do them in separate posts.

The first was the statement that a dilution equal to Avagadro's number meant that there was no molecule of the original substance left, this is not actually correct. What it actually means is that it's extremely unlikely that a molecule or more remains. You can even go further and ask 'if I dilute something an infinite amount of times, what's the probability of the original substance being left?'. This probability turns out to be, if you do the maths, zero. However this does not necessarily mean that there are no molecules left, since it is possible that each time you kept some liquid there was a molecule in that volume. just that it's extraordinarily unlikely.

The next is a bit of a bug bear of mine and that was the statement that it works if you believe it does due to the placebo affect. Just no. The Mersey Side Skeptical society put it well when they compared it to lemonade. If you conducted a trial with a placebo to test if lemonade helped with headaches and it worked as well as the placebo I can't imagine anyone therefore saying that lemonade helps with headaches if you believe it does (although I also tend to find it impossible to underestimate humanity). It didn't work, case closed. In my mind the only difference between lemonade and homeopathy is that there are not a number of people who base their livelihoods saying that lemonade will aid what ills you.

It is an otherwise good podcast. Just in case that didn't come across. ;)