Notes:
So let’s return to the measurement problem. As we have seen the measurement ‘changes’ the quantum description. This of course has troubled physicists right from the early years of QP.
The reason is that it was clear that by simply postulating that a measurement device defined the measurement was not enough. A measurement should also be described physically and thus although the quantum description might become quite complex there seems to be no clear reason to assume that at some point the collapse occurs. This has been shown most clearly in the thought experiment of Schrodinger’s cat which if we let the photon in case of reflection trigger a hammer which releases a poisson and in cese of transmission not trigger the hammer. If we take seriously the view that since there is nothing in physics that forces the collapse it should be something outside of physics and the assumption is that Consciousness is instrumental in bringing about collapse. Thus until cosncious observation is made the cat is also in superposition. The most outspoken proponents of this idea nowadays are Stapp and Walker.
This proposal seems rather farfetched but let me stress that the problem is immense and other proposals like the many world or many mind interpretations are seriously considered.