I know there are many wavefunction collapse models - but with regards to the Copenhagen interpretation the idea is that a measurement will cause something to collapse into a particular state. What does the term "measurement" refer to? It makes one think of only something that a conscious being does. Are all wavefunctions that interact with a thing in a collapsed state, or since we have yet to measure them are they in a probabilistic state? Do we say that things we are unaware of, or mind-independent, interact with each other in a collapsed state? After all, what would it mean to say that probabilistic states in remote galaxies are interacting with each other? I ask this because after reading Wheeler's "delayed choice" experiment it seems there's no definite series of events that happen, even in the past, until something is measured. My first thoughts in response were "What about all the things this photon interacted with?", "What if there was another observer in one of these galaxies"? I apologize for the broad nature of this question - and the perhaps confusing elements I have thrown in but I find this all very exciting and am just seeking some clarification.