 According to this definition, implementation shifts from level to level: a set of algorithms defining a computational system are implemented as procedures in some formal language, as instructions in a high-level language, or as operations in a low-level programming language. An interesting question is whether any system, beyond computational artifacts, implementing procedures of this sort qualifies as a computational system. In other words, asking about the nature of physical implementation amounts to asking what is a computational system. If any system implementing an algorithm would qualify as computational, the class of such systems could be extended to biological systems, such as the brain or the cell; to physical systems, including the universe or some portion of it; and eventually to any system whatsoever, a thesis known as pancomputationalism (for an exhaustive overview on the topic see Rapaport 2018).