Just wondering if anyone can explain to me why it is thought necessary to say that consciousness (an observer) is necessary to account for certain things in Quantum Physics (e.g. for the collapse of the wavefunction), rather than just say that a measuring device (with or without a conscious observer) is sufficient. I can certainly see that experiments such as the delayed choice quantum eraser experiment, stretch our understanding to the limits, but is it actually necessary to invoke the conscious observer? When various writers on quantum physics say that wavefunctions collapse when "observed", that waves appear as particles when "observed", often the distinction between "observer" as a conscious subject, or as a measuring device which has no consciousness, no subjectivity (in the technical sense of "subjective", rather than the perjorative sense), is left unclear. Certainly Schrodinger and his cat was not happy with the idea of a conscious observer collapsing the wavefunction. I am a layperson and have no mathematical background, but would be interested to know what you think.