https://en.wikipedia.org/wiki/John_von_Neumann#
https://youtu.be/J-F-m77Ghy0?si=bT_WTo9wAs9jlg24
John von Neumann (1903–1957) did not explicitly say that “consciousness causes the collapse of the wave function” in a simple or dogmatic way. However, his mathematical formulation in “Mathematical Foundations of Quantum Mechanics” (1932) opened the door to this interpretation, and many later thinkers attributed that position to him—rightly or wrongly.
What von Neumann actually did:
In his 1932 book, von Neumann:
- Formalized quantum measurement theory, introducing the concept of the “cut” between the quantum system and the measuring apparatus.
- Argued that the chain of measurement (from system → apparatus → observer) must be cut somewhere, and that this cut could in principle be placed arbitrarily far up the chain—even including the observer’s consciousness.
- Noted that the wave function collapse is not derivable from Schrödinger’s equation alone, and that some kind of intervention is needed to produce definite outcomes.
So where does
consciousness
come in?
- Von Neumann did suggest that ultimately, the collapse must occur at the level of the observer, since physical systems—including measuring devices—can themselves be treated quantum mechanically.
- This led later interpreters (especially Eugene Wigner) to suggest that consciousness is what collapses the wave function—a position now known as the von Neumann–Wigner interpretation.
However:
- Von Neumann never explicitly said that consciousness causes collapse in the metaphysical or ontological sense.
- He left open where the cut is placed, and never claimed collapse was caused by consciousness as a definitive doctrine.
- His work mathematically accommodated the idea that consciousness might be the final step in the measurement chain, but this is not the same as making a philosophical claim.
In short:
Von Neumann provided the formal groundwork that allowed for the interpretation that consciousness plays a role in wave function collapse, but he never unequivocally claimed that it does. That leap was made more explicitly by later thinkers, particularly Eugene Wigner.
Would you like a comparison of von Neumann’s interpretation with other major interpretations of quantum mechanics, like Many-Worlds or Bohmian mechanics?
