Do you know that homeopathy doesn't work, or do you just lack belief that it does?

[robvalue]

All we can do is give a measure of confidence. Claiming absolute certainty about reality is ridiculous, so I don't think it's even worth including on a scale. 0% could be maximum confidence that a statement is false, and 100% maximum confidence that it is true. It's similarly pointless to talk about solipsism or baseless worldwide conspiracies, unless you're specifically interested in those topics.

I'd say I have about 0.1% confidence that diluting active ingredients improves their potency, in general at least. All available evidence I'm aware of points to this being false.