The wave packet function is not real in the sense that you can’t touch it in the classical manner. It is also not real in the sense that we have chosen a particular model to represent the true quantum STATE. However the quantum state is real. In fact it is the only reality! Our representation of the quantum state by a wave packet is to allow us to visualize a little BIT what is going on. Our real contact with the quantun state is by measuring |ψ|2. And of COURSE since it is a probability, sometimes you have to measure it lots of TIMES. We will see, though, that the SITUATION is not always as vague as it appears in the two-slit experiment.

The wave packet function is not real in the sense that you can’t touch it in the classical manner. It is also not real in the sense that we have chosen a particular model to represent the true quantum state. However the quantum state is real. In fact it is the only reality! Our representation of the quantum state by a wave packet is to allow us to visualize a little bit what is going on. Our real contact with the quantun state is by measuring |ψ|2. And of course since it is a probability, sometimes you have to measure it lots of times. We will see, though, that the situation is not always as vague as it appears in the two-slit experiment.