André Costa

1. The Paradox

Quantum objects are thought to be physically indefinite, described by a wavefunction, until they have a causal connection, such as interaction with a measuring device, and then become definite. On the other hand, large objects are thought to be physically definite at all times, with clear positions in spacetime.

This points to a supposed difference in the rules and ontology that govern both the quantum and large scales, each with its own physics. Much of modern physics is specialized in the attempt of reconciling these apparently different realities.

2. The Hypothesis

I argue that there is no division between the rules that govern the macro and the micro, and that relativity’s mathematics had already included superposition and collapse from the start, although not yet recognized as such. This is present in its view of simultaneity.

When events A and B are causally connected, all observers agree on their temporal ordering, such as A happened before B. However, if A and B are spacelike separated, different observers will conclude different orderings. One may say that A happened before B, another that B occurs before A, and yet another that they are simultaneous. This is superposition of causal orderings.

Both A and B exist, but they have no causal connection, therefore all causal orderings are valid, depending on the observer. The causal interaction between A and B is the source of collapse of such superposition. In short, objects which are not interacting with each other are also not physically definite in relation to each other. Once they interact, however, their positions become definite.

The same is true in quantum mechanics. When a particle is isolated enough, not in interaction with, e.g., a measuring device, it is physically indefinite, existing in superposition. Upon interaction, which is a causal connection, reality forces a definite causal ordering, a state, relative to the observer, for all observers.

This note proposes that the difference in observations between classical and quantum is not size, big vs small, since the rules of physics are the same for both; but rather causal density. Large objects interact with the environment at all moments, through gravity around other large objects, interaction with light, heat, and so on, and thus have definite positions. Quantum-sized objects, however, are more isolated, free of causal networks, thus remaining in the wavefunction.