devilsadvocate said:Suppose in law of identity "A" includes the object and also all the coordinates of the object (including time). Two otherwise identical objects, but at different coordinates, wouldn't qualify A=A. When A is fully and exactly defined, there's no problem(?) (other than with how we in ordinary language understand identity as a continuum, but that's a different question)
Objectively, it might include its coordinates but subjectively? Do you define yourself by where you are or where you're going (not metaphysically or metaphorically)?
I ask because, there is no position on this planet for which we can stand and mark the space-time coordinates of any individual. The more accurately you measure one variable, the less accurate you can measure others.
Matter Wave Interpretation of the Heisenberg uncertainty principle states:
According to the de Broglie hypothesis, every object in our Universe is a wave, a situation which gives rise to this phenomenon. Consider the measurement of the position of a particle. The particle's wave packet has non-zero amplitude, meaning that the position is uncertain, it could be almost anywhere along the wave packet. To obtain an accurate reading of position, this wave packet must be 'compressed' as much as possible, meaning it must be made up of increasing numbers of sine waves added together. The momentum of the particle is proportional to the wavenumber of one of these waves, but it could be any of them. So a more precise position measurement, by adding together more waves, means that the momentum measurement becomes less precise (and vice versa).
The only kind of wave with a definite position is concentrated at one point, and such a wave has an indefinite wavelength (and therefore an indefinite momentum). Conversely, the only kind of wave with a definite wavelength is an infinite regular periodic oscillation over all space, which has no definite position. So in quantum mechanics, there can be no states that describe a particle with both a definite position and a definite momentum. The more precise the position, the less precise the momentum.