It's often claimed that in *Mathematical Foundations of Quantum Mechanics* Von Neumann concluded that it's the observer's consciousness that collapses the wavefunction (Process 1).

But I am reading Chapter 6 of the book (both original and translation) word by word, and I don't find this conclusion. The closest is where he mentions the observer "abstract 'ego'" as one of the possible endpoints of the measurement chain (p. 421 in the 1955 translation).

This doesn't seem a "conclusion" to me. Is he more explicit elsewhere (in the same book or other writings)?