Digression: A dictionary defines atomic as: "a single irreducible unit or component in a larger system" but that does not account for the complex nature of the issue. For example, an atomic element such as a hydrogen atom is comprised of protons and electrons and thus the atomic element is reducible. This notion may be both historical or simply a matter of convenience. For example: an electron may also be reducible and the product of the reduction may itself be reducible. A number is reducible to digits, digits to pixels, pixels to RGB components, RGB components to photons, photons to wave functions and eventually Heisenberg states that everything has an element of uncertainty so that any explanation can be reduced to anything (theoretically), such as a banana, so it is better just to drop this subject before this digression moves on to Gödel's incompleteness theorems.