Einstein put forward his theory of general relativity 100 years ago. His prime insight concerned the reciprocal relationship between mass and spacetime. Mass (matter and energy) warps spacetime (our three observed physical dimensions plus time) and warped spacetime determines how objects move around mass. Mass in motion always moves in straight lines. However, in the presence of massive objects, those straight lines follow the curves of warped spacetime. Thus things fall.
Einstein also contributed to the elaboration of quantum mechanics. But quantum physics and relativity seem to be fundamentally different ways of understanding reality. The former reduces all we observe to a realm of particles and waves that remain intrinsically probabilistic. The latter places reality into a universal geometrical framework of space and time. Einstein was uncomfortable with quantum physics because of its probabilistic nature – “God does not play dice with the universe” – and because until observed, particles also exist as waves. A further issue for Einstein was the apparent implication of quantum physics known as entanglement.
Quantum entanglement occurs when two or more particles are generated or interact in such a way that they share the same wave function (quantum state). When that happens, no matter how far apart those particles may move away from each other – even to opposite ends of the universe – they remain entangled: measurement of one – collapsing its wave function – also determines the measurement of the other. This bothered Einstein – he termed it “spooky action at a distance” – because the two particles seem to communicate through space instantaneously and – more to the point – faster than the speed of light. For Einstein, the speed of light is a fundamental constant and nothing can go any faster. But experiment has consistently verified the phenomenon of quantum entanglement. Most recently a group of Dutch physicists gave what is widely seen as definitive proof that entanglement across distance is real and reveals that reality is in some way non-local.
Non-locality implies that entangled things exist in a relationship that is not determined by the local conditions that impinge upon those things. In other words, when one of the things is measured, the qualities of the far distant formerly entangled thing are not determined by where that thing is but by some deeper reality that is not local to the thing itself. Non-locality implies that there is some more fundamental level of reality that exists outside space and time.
We live in a universe in which time and space do exist. We travel through space (in any direction of three directions) and time (only forward). Things with mass travel travel no faster than the speed of light. At the speed of light, everything happens at the same instant because time does not pass. If we could be that massless surfer riding a photon created at the moment of the Big Bang, we would experience everything and everywhere that photon would ever be at the same instant.
We experience time as passing because we live in a world of matter and energy, which seems to give rise to spacetime. Our consciousness exists in time as our body exists in space. But non-locality points to a reality in which the universe exists without time or space as one object in which all time and space exist at once. We appear not to experience this deeper reality outside the realm of quantum experimentation (though it may make it possible someday to have quantum computing). But non-locality – as St. Thomas Aquinas might argue – points to consideration of First Cause and Ultimate Reality. That is spooky.