# The (quantum) world existing AND non-existing

• I
Gold Member
Can we suppose that a quantum property (like spin, polarisation, velocity, position) becomes a potential, a probability, when we are going to measure it? Can we say that this property does not exist while remaining unmeasured, and that when measured takes on a value that depends on both the measured quantum object and the measurement apparatus, so that after measurement we can't claim that we measured the property itself?

What I'm driving at is that the property as a probability cannot (ontologically) be claimed to exist or to not exist, and after measurement, we have a value that does not represent the value of the property, because the measured value is a combination (entangled state) of apparatus and quantum object, so that the property measured does not represent a property that actually existed.

The property is as it were 'created'. So after that, it exists in the measurement result, however the result is not representative of something that existed and as such does not indicate anything (ontologically) existing.

So I figured that we can't claim reality is real nor that it does not exist. Things exist and not-exist.

I figured that the branches of the many worlds interpretation don't represent anything real 'per se', but that they are real and not-real at the same time (possibly to some degree). For instance: if we have in some basis the superposition ##\frac{\sqrt{2}}{\sqrt{3}}| a \rangle + \frac{1}{\sqrt{3}}| b \rangle##, then we have the potential of two realisations (##| a \rangle## and ##| b \rangle##). In MWI we have both after measurement. My view is that they might both to some degree be real and not-real as indicated by their amplitudes. What becomes real is relative to the observer (the measurement).

So not so clear as I hoped to be but hey, this is complicated stuff. I am looking out for your views on this.

So my main question is this: is the world both real and not-real? (not solely with respect to MWI)