Chapter 4 argues that those material objects that, in the Categories, would fall under the category of substance qualify as hylomorphic compounds (i.e. they have matter and form). It presents three arguments in defence of the thesis that artefacts have forms. The first argument is that artefacts undergo genuine unqualified coming-to-be (or substantial change), as opposed to the mere acquisition of a property by a substrate. Related to this argument is the crucial Aristotelian distinction between per se unity and accidental unity. The second argument is based on Aristotle’s application of the ekeininon-rule to artefacts, which reveals that the identity of an artificial object cannot be reduced to its matter. (The third argument is that Aristotle’s application of the synonymy principle to artefacts shows that the form in the mind of the artisan is identical to the form present in the actual artefact, insofar as it is thought, and that the artisan’s use of tools represents the stage at which the artefact’s form is in potentiality.

Chapter 5 argues that the identification of the form in the mind of the artisan with art amounts to ascribing it the role of efficient cause. As the chapter explains, the form in the mind of the artisan is responsible for both qualified and unqualified coming-to-be. Art is the only form that is an efficient cause, in contrast to the form inherent in the artefact. By resorting to Aristotle’s biological works, the chapter clarifies how artefacts come to lack an inner principle of their behaviour and how this is connected with their lack of an inner principle of unqualified coming-to-be. Two theses in particular are challenged. The first is that the form is transmitted from the mind to the object and, as a result, the form of an artefact is potential, because this is the status of the form in the mind in the artisan. The second thesis is that artefacts are not substances because their forms are not principles of changes. The chapter concludes with a reflection on the relation between eternity and substantiality.

In the early treatise Ennead V.9, Plotinus discusses whether the arts are there in the intelligible realm, and concludes that they are at least partly. The chapter’s first part discusses a number of questions that arise. What is exactly the principle of division for which arts or which parts of an art are in the intelligible realm? What is the status of the arts in the intelligible world? Are there Platonic Forms of the arts? In a later treatise, V.8., Plotinus argues that rather than imitating sensible objects, some artists concerned with producing beautiful sensible objects imitate the intelligible paradigm of beauty. Emilsson discusses this claim, which seems a clear deviation from the account of mimetic art in Plato’s Republic. In the latter half of the chapter, Emilsson addresses Plotinus’ demythologisation of Plato’s Timaeus. Plotinus replaces the Demiurge of the Timaeus with the universal intellect and the World-Soul, which do not deliberate. However, Plotinus does not reject entirely any craftsman model, for he appeals to performance arts, which do not involve deliberation, in explaining how natural processes flow from higher principles. Emilsson then discusses what sort of conception of the arts lies behind this view.