Quantum mechanics distinguishes itself from classical physics via the presence of entanglement. Classically, one is conditioned to imagine situations wherein components of a single system may be separated into non-interacting parts, which we can separately examine, and then put back together to reconstruct the full system. This intuition fails spectacularly in quantum mechanics, since the separate pieces, whilst non-interacting, could nevertheless be entangled. As Schrödinger put it quite clearly [1]: The best possible knowledge of a whole does not necessarily include the best possible knowledge of all its parts, even though they may be entirely separate and therefore virtually capable of being ‘best possibly known’, i.e., of possessing, each of them, a representative of its own. The lack of knowledge is by no means due to the interaction being insufficiently known – at least not in the way that it could possibly be known more completely – it is due to the interaction itself.