The metaphysics of artefacts is increasingly gaining the attention of contemporary metaphysicians, particularly among supporters of hylomorphism, who all refer to or draw on Aristotle. However, there is no consensus about the place of artefacts in Aristotle’s ontology. Not only that, but there is no consensus as to whether Aristotle even has a single coherent account of artefacts in the first place. This book has shown that Aristotle does present a coherent and detailed account of artefacts. I shall now summarise the conclusions that have been reached in a manner that is sensitive to currently discussed issues, so as to provide a guide for the contemporary (Neo)-Aristotelian debate.

With regard to the class of ordinary objects – which includes artefacts, but also living beings – Aristotle is neither an eliminativist, nor a permissivist, nor a conventionalist. Ordinary objects are, for Aristotle, a privileged subject matter. The class of ordinary objects is, however, internally diverse, and artefacts and living beings differ from one another in metaphysical status. While contemporary metaphysicians defend the claim that artefacts are of interest by privileging the class of ordinary objects as a whole and articulating metaphysical accounts that work equally well for living beings and artificial objects, Aristotle’s focus on ordinary objects is significant in that it includes a metaphysical explanation that is specific to artefacts. Artefacts do ultimately deserve a place in our ontology: a place that is not shared with living beings, but which might be shared with other human-dependent objects.

One general controversy concerns the definition of the class of artefacts. Here, the pertinent questions are ‘What is an artefact?’ and thus ‘What things are artefacts?’. Aristotle defines a typical artefact as a contingent object that differs from a natural being in that it lacks an inner principle governing its behaviour and differs from other human-dependent objects in that it is typically brought about by a skilful and learned maker. The criterion that there be no inner principle of this sort excludes natural beings and artificially produced members of natural kinds (e.g. the domestic olive) from the class of artefacts. The cognitive equipment required by technê, as an external principle, excludes animal artefacts, unintended products of human activity and products of mere experience from the spectrum of artefacts in the strict sense.

Aristotle’s notion of what constitutes an artefact is narrower than modern ones. For instance, for Reference HilpinenHilpinen (1993), for something to be an artefact it needs to have an author; according to Reference ThomassonThomasson (2003, Reference Thomasson, Margolis and Laurence2007b), it needs to be an intended product of human activity; in Reference DipertDipert’s (1993) view, it is an instrument that has been modified such as to be recognised as having been intentionally made for a certain purpose. Aristotelian artefacts require more than just an author and more than just an intention, even if they are accompanied by a certain purpose. For something to be an artefact, it also needs to undergo unqualified coming-to-be. In other words, it needs to be a new item that is added to the furniture of the world. In this sense, Aristotle is able to escape the charge of promoting an ‘easy ontology’; that is, the charge that the world would be populated with endless things and kinds, if intention alone were sufficient to produce artefacts. In fact, on Aristotle’s account, for something to come into being, there needs to be a form driving the unqualified coming-to-be, as well as an intrinsic change in the matter. When combined, these two requirements impose serious restrictions on the possibility of creating new items and thus make Aristotle less vulnerable to the accusation of promoting an easy ontology. Found-objects and ready-mades are not artefacts, first and foremost because they do not undergo unqualified coming-to-be and thus fail to constitute new items in the world. The same principle also applies to conventional objects, such as dinner and breakfast, which do not undergo unqualified coming-to-be, but are best understood as matter that acquires a non-substantial property. By contrast, artefacts undergo unqualified coming-to-be and acquire a substantial form. This state of affairs shows not only that Aristotle cannot be charged with offering too easy an ontology but also that he treats the categories ‘artificial’ and ‘conventional’ differently. Artefacts are existentially mind-dependent, but are not conventional items.

The fact that artefacts undergo unqualified coming-to-be and therefore acquire a substantial form introduces the problem of how to understand the nature of this form and, consequently, how to understand their essence. It is traditionally accepted that Aristotle holds an essentialist view of ordinary objects, particularly living beings. Ordinary objects possess properties and they possess some – though not all – of these properties essentially. Ordinary objects are not only composed of properties (bundle theory), but are constituted of matter and form. While the hylomorphic character of natural substances in Aristotle is widely recognised, the hylomorphic character of artificial objects is often denied and rejected. Aristotle scholars generally endorse the view that artefacts lack forms or that their forms are mere accidental properties of a given chunk of matter. Artefacts do, however, possess an inherent substantial form, and therefore an essence. Now, if we understand the nature of artificial forms, this leads us to comprehend the extent to which artefacts differ ontologically from living beings. In the contemporary debate on hylomorphic imprints, the essences of artefacts are singled out in different ways. According to Reference Thomasson, Margolis and LaurenceThomasson (2007b), for instance, the essence of an artefact is identical with the intention of the maker. According to Reference EvnineEvnine (2016), the essence of an artefact coincides with the act of its creation. By contrast, Reference BakerBaker (2007) and Reference ElderElder (2004, Reference Elder, Margolis and Laurence2007), though in different ways, identify the essence of artefacts with functions. The latter position is closest to that of Aristotle. The functional account of forms of artefacts is Aristotelian in that it posits a form that is inherent in the object and that has genuine, mind-independent existence – albeit caused by us. Moreover, the form of a house can be identified with its function (i.e. sheltering). The intention of the maker just is the function of the object insofar as it is thought. The act of creation is neither identical with the artefact in question, nor does it transmit an essence to the object; instead, it simply enables the object to come into existence. However, the functional account is only half of the story. Forms of artefacts are specifiable as functions, but they are not primarily functions from a strictly metaphysical perspective. Forms, whether artificial or natural, are primarily structuring principles, or principles of organisation, in virtue of which an individual is the kind of thing that it is and a multiplicity of components is unified into a single thing.

In this respect, forms of artefacts are like forms of living beings. Nonetheless, there are some differences: first, forms of artefacts are not eternal; second, they are not inner principles of motion and rest (i.e. they do not behave like nature in natural beings or the soul in living beings). However, these two aspects on their own do not resolve the issue of substantiality. In other words, although the form of a house is not eternal and is not an inner principle of motion and rest, this does not constitute an immediate reason for denying substantiality to artefacts. The composition of a new object does not occur only when life obtains (contra Reference Van InwagenVan Inwagen 1990). Living beings might well turn out being the only substances, but this does not mean that only living beings exist or even that they are the only hylomorphic compounds.

An important difference between artefacts and living beings lies in the relationship between their form and their matter. Forms of artefacts entertain a many-to-many relationship to the diachronic matter, as well as a contingent relation to the synchronic matter. This situation is, in turn, explained by the fact that the matter is not already equipped with a principle directed towards the form (i.e. a moving principle). Although this is the right approach to solving the problem of the substantiality of artefacts, it still does not provide us with the immediate reason why artefacts are not substances. The reason for this is that it works with a description of the form as function, which is unable to ground the metaphysical status of artefacts and is not ultimately related to any established criterion of substantiality.

By contrast, the description of forms as structuring principles of matter, considered as parts, represents the immediate reason why artefacts are not substances at all. Because they are structured extrinsically, artificial parts are in actuality, even after the intervention of the artisan. This state of affairs contravenes the substantiality criterion laid down Met. Z 13, according to which no substance has parts present in it in actuality. A natural substance such as an animal is not composed of parts present in it in actuality, but only of potential parts whose identity depends on the identity of the whole. An artefact, such as a house, is composed of parts present in it in actuality, whose identity remains independent from the identity of the whole. Regarding the question of whether objects have their parts essentially, Aristotle would answer by making a distinction: while natural parts are themselves essentially parts of a given natural being, artificial parts are not themselves essentially parts of a given artefact. The handle, the wall and the bottom of a porcelain mug – all of which are ultimately mere porcelain – are not essentially parts of a mug. However, in order for the mug not to cease to exist, the essential parts need to be preserved. The essential parts cannot be lost without the object ceasing to exist. A mug can gain and lose a handle, but it always needs to have a bottom. If a hole is drilled in the bottom, the mug loses its structuring principle and ceases to exist. This takes us to the well-known puzzle of Theseus’ Ship and the problem of the identity conditions of an artefact. The identity of Theseus’ Ship, as a concrete individual object, derives from its structuring principle and its particular matter. When the matter is replaced by new matter, it is possible that the ship is destroyed – to the point where it cannot perform its function when acted upon – and that another ship comes into existence when the function is restored. By contrast, if the matter is replaced by the very same matter, the ship might be destroyed when the process of replacement reaches the point at which the ship cannot sail, but it might also come-to-be again when all of the parts are put back in their place. On Aristotle’s view, there is nothing wrong if the ‘life’ of an artefact may be temporally discontinuous. If we suppose that the pieces that are removed are safely stored in a warehouse, once they are put back together with a view to the same function, Theseus’ Ship comes into existence once again. The identity of a concrete particular object thus depends on the structuring form, conceivable as function, and the particular matter employed. There is, however, a final, pressing worry: if artificial parts are in actuality, it seems that Aristotle is exposed to the problem of coinciding objects, especially in the case of artefacts. The problem of coinciding objects does not apply in the case of living beings, since in this instance it is not case that there exists both the matter and the object that is composed of it; rather, as soon as the living being is, the matter is not – or, at least, is only in potentiality. In the case of artefacts, however, because their parts are in actuality, it seems that there exists both the matter and the object that is composed of the matter, which coincides with it. However, Aristotle would say that the structuring principle is along, around or between the matter, but not in the matter, in such a way that it never coincides with the parts. In the more difficult case of single-material objects, such as the brazen statue, the form of the whole has priority over the form of bronze, since it organises the matter in a way that is still reducible to forming a plurality into one single new thing.

Aristotle’s theory of artefacts is therefore essentialist and hylomorphic. Artefacts are new items that populate our everyday world and deserve a place in our ontology. They possess inherent substantial forms, which makes them something more than mere heaps. Their forms depend existentially on the intervention of the artisan. However, they cannot be identified with the artisan’s intentions; rather, they ought to be identified primarily with structuring principles, secondarily specifiable as functions. The presence of forms confers unity on artefacts, albeit only to a certain degree, given that their parts are in actuality. Aristotle thus proposes a scalar view of unity accompanied by a binary view of substantiality. Precisely because artefacts are not unified to the highest degree (in contrast to those beings that lack matter altogether, such as the heavenly bodies, or that have matter in potentiality, such as sublunar living beings) artefacts are not substances at all. Although they are not substances, insofar as their forms confer some degree of unity on them, artefacts exist and contribute to furnishing the world.