Abstract

Each inhabitant of our world Gilbert calls an id quod est or subsistens. Its main constituents are the subsistentiae and these are accompanied by the 'accidents', quantity and quality. The subsistent owes its status to a collection of inferior members of the Aristotelian class of accidents, which to Gilbert 's mind are rather 'accessories' or 'attachments from without'. The term 'substantia' is used both to stand for substance and substantial form, i.e., that by which something is subsistent. The collection of subsistentiae or the forma totius is called natura. However, 'natura' is also used to stand for either just one subsistentia or all the forms found in a subsistens even including its 'accidental' forms. The inclusion of all kinds of accidents is seldom found in the intension of the word 'natura'. One of the key notions featuring in Gilbert 's ontology is esse aliquid. 'To be a-something' has a threefold import. First, it means 'to be only some thing', and to miss perfection. Second, it has the positive sense of 'being a something', i.e. 'being determinate and well-delineated', not indefinite, not formless that is. Third, 'to be a something' implies concreteness, corporealness and singularity