 The claim about the identity of grammar across languages is based on the assumption that (1) all humans conceptualize external reality in the same way, even though they express their concepts in ways that are culture dependent (as taught by Aristotle in De interpretatione 1); and (2) that this conceptualization does not only result in core concepts like run, pain but also in an awareness of different modifications of the core things underlying the concepts, different modi essendi “modes of being”. This awareness, in turn, means that we harbor different corresponding modi intelligendi “ways of understanding”, that we can then encode in sound, creating words with different modi significandi. How this encoding is done, is a matter of convention, as Boethius repeatedly stresses. What one language expresses by means of case endings, e.g., may be lexicalized in another; the difference is only skin-deep (“accidental”), he holds. He may have held that all languages actually have the resources for expressing all reality-based modes of signifying; at least he held that all languages hold the potential for so doing. One of the consequences of Boethius’ views is that although grammar maps the ways in which words may signify, it does not allow one to predict what any actual word in any language means, and whatever some word means is irrelevant for its grammatical categorization: “chimera” and “nothing” are nouns as truly as “horse” and “thing”, for grammar is about how, not what, words signify. Boethius’ conception of grammar as a science of linguistic structure, not content, was matched by a similar conception of logic (Ebbesen 2016).