I’ve thought for a long t— er… for a while that our perception and understanding of time is flawed, but I’ve been led to these conclusions by purely physical considerations.
The EPR paradox is a gedanken experiment involving two entangled particles; when they’re far enough apart for communication between them to take some non-trivial time, one entangled quantity of one of them (eg, position) is measured with high precision. The Heisenberg Uncertainty Principle then says that the error in that particle’s velocity (in this case) becomes so large that measurements of it give wildly inaccurate results. In symbols, Δx . Δp ≥ ℏ/2, but only for the measured particle. If the other particle’s velocity is measured with the same precision, and at the same time as the position of the first, it’s possible to deduce both the velocity and position of both particles to a high precision, in violation of HUP. SR says that information can’t be communicated faster than light, so the only ways for this to be possible are (a) hidden variables — that is, there are some variables that we don’t (and can’t) know about that describe the quantum state (this was EPR’s preferred solution), (b) many-worlds — measuring one particle causes the universe to split into two almost identical universes, with the measured states in one of each universe, or © time works differently to what we expect (considered unphysical at the time.) While it is impossible to conduct this actual experiment (since the experimenter would have to know in advance where the particles were for the measurement, and thus would have to know their positions and velocities in advance, it’s been shown that Bell’s Inequality actually describes an equivalent experiment that can be (and has been) performed.
In the philosophy of science, there’s an idea that things only happen if they’re observed to happen (so the moon doesn’t exist if no-one’s looking at it.) Since photons only exhibit their existence when their energy is absorbed, it can be (and has been) argued that photons only actually exist when they’re destroyed. So a virtual particle is emitted, tracing the path the photon would take, until it meets something to absorb it, at which point it sends a message back in time and the actual photon is emitted (possibly many billions of years lated.)
If Young’s double slit experiment is conducted with single photons, the interference pattern is seen, unless the slit the photon passes through is observed, in which case the interference pattern is destroyed and an image of the two slits is displayed. It makes no difference when the observation is made. Even if the particle is allowed to impinge on the screen, and the observation of which slit it passed through is then made, the interference pattern is destroyed.
This last is a specific case of Wheeler’s delayed choice experiment, in which the behaviour of a particle is chosen by the experimenter after the particle has made its choice.
All of these together suggest to me that our understanding of time is flawed.