A comment from Clive J. Grant reads:
I'm not permitted to tell you what lay behind it, but I travelled to
Princeton, in the company of a textile expert, to discuss something with
Einstein. What I remember is that he said,
If I give you a pfennig,
you will be one pfennig richer and I'll be one pfennig poorer. But if I
give you an idea, you will have a new idea, but I shall still have it,
too.
I never did get the idea, but I did get the aphorism.
JOC/EFR January 2000