[Marxism] Kautsky Quote Needed

[Ian Angus]

For an article I'm writing, I am looking for a brief quotation from Karl
Kautsky, which I saw once but now can't find.

I think it was written in the first decade of the 1900s. In it, Kautsky said
something to the effect that the fact that an idea comes from the ruling
class or may serve ruling class interests doesn't mean that the idea is
wrong.
Can anyone help?

Ian Angus
Climate and Capitalism
www.climateandcapitalism.com