From A
Geoff Stanley writes in his letter that “superposition of quantum states is only determined by observation… (and this may be the) ultimate example of top-down causation” (12 October, p 31). This is offered as an example of the macroscopic world impinging on the microscopic.
This would be true only if the “decision” to observe is itself not produced by a prior combination of microscopic states. I don’t think our knowledge of consciousness – as it stands today – can shed any light on this.
Chandigarh, India
. K. Vijayakumar
