"Everything that we talk about, everything that we regard as existing, postulates consciousness.

Ummm...Planck was a really bright guy, but I don't think he was up to speed in the details of philosophic logic.

His statement above is, as it stands, 'trivially true' in that we must BE conscious in order to "talk about" anything. Planck is no longer with us, and presumably not 'contemplating' anything, but we still contemplate him. If I could have interviewed him..(I was only 8 when he died).. I would have asked him what he thought 'existed' before we came along to experience it.