1 Aristotle

According to the Oxford English Dictionary (online version), in contemporary English usage the word ‘nutrition’ carries four meanings:

1. The action or process of supplying, or of receiving, nourishment or food.

2. That which nourishes; food, nourishment.

3. The state or condition of being (well or badly) nourished; a person’s state of health considered as a result or indicator of (good or bad) nourishment.

4. The branch of science that deals with nutrition (sense 1) and nutrients, esp. in humans; the study of food and diet.

In light of the above definitions, ‘nutrition’ seems an appropriate English rendering for the Greek words τροφή or τὸ τρέφειν/τρέφεσθαι, which are used by authors of the 5th and 4th centuries BCE to refer to processes, activities or functions related to nourishment, or even to kinds of food or nutriment that are able to nourish or procure sustenance. The term θρέψις is not attested before the 2nd century CE. In Galen θρέψις is acknowledged as one of the three main activities (ἐνέργειαι) of nature – the other two being growth and generation (De facultatibus naturalibus I,5, K. II,10).

Specifically, rendering 4 resonates with what in Hippocratic texts is sometimes referred to as dietetics, that is, that part of the medical art (and not science) which deals with diet (δίαιτα). The gradual development of dietetics into a cornerstone of medicine was set off by medical ideas of that time which are closely akin to rendering 3, most notably the belief that a person’s state of health depends heavily on the food (s)he consumes. In one of its two main meanings (the other being ‘rearing’, ‘bringing up’), τὸ τρέφειν, apart from the act of nourishing, refers to the substances that are able to nourish (so, rendering 2). Now concerning nutrition as a bodily function related to a set of individual physiological activities of certain body parts, Aristotle seems to deserve, at least to a certain degree, credit for being the first to explicitly make such a progress (cf. de Partibus Animalium ΙΙ,3, 650a9; ΙΙΙ,14, 674b10, 19). Of course the ancients did not talk about metabolism, in the strict biochemical sense of the word, nor did they reflect on matters related to the energy value of food. They did nonetheless speak of assimilation of food as a sort of change taking place due to mutual interaction, in some cases of opposite, while in others of like qualities or powers. In the place of the brain, some of whose networks are nowadays considered to be associated with the control of feeding, the ancients put the soul.

Aristotle was the first to systematically describe a particular part of the soul as responsible for the physiological process of nutrition. This is the nutritive part, which is acknowledged as the necessary and sufficient condition for life, and is therefore held to be shared by all living beings, plants, animals and humans. Nevertheless, as will become clear from the contributions to this volume, nutrition is far from being the only act in which the nutritive soul, biologically speaking, manifests itself. Breathing, cooling, growth, reproduction and, to a certain degree, sleep and vigilance are directly connected to nourishment from food, which explains why they all fall within the nutritive soul’s realm of responsibility. Aristotle did not, thus, single out, say, a ‘breathing/cooling’ or a ‘formative’ psychic part, but rather subsumed the respective functions, along with a variety of other functions, under the umbrella of the nutritive faculty. And he did so not only because these functions are common, as he repeatedly insists, to all living things, but also because, in order to be performed, there must be some form of direct interaction between them and phenomena occurring during the nutritive process.

Overarchingly, addressing the fundamental problems concerning the nutritive part of the soul as well as the variety of physical manifestations it directs lies at the core of this volume. Its principal aim is to highlight the much-neglected multifacetedness of the ‘lowest’ part of the soul and its physiological aspects, thus opening the way for further investigation of Aristotle’s and his successors’ views on the subject. Divided into two sections, ‘Aristotle’ and ‘Aristotelianism’, each made up of 8 fresh contributions, this volume lays no claim to an exhaustive coverage. The variety of digestive residues, the contribution of evaporation to the nutritive process as a whole, or even the role of heat and cooling in animals that do not respire are only a few examples of the many topics that are directly related to nutrition and nutritive soul and need further clarification.

The contributions to this volume centre around two crucial research topics which have greatly troubled thinkers since antiquity, and over which floods of ink have been poured: the relationship between body and soul, and the partition of the soul. It is true that the nutritive soul and its physical manifestations have not been discussed in the relevant literature as adequately as the other two parts of the soul, the perceptive and the rational, although it has been almost two decades since Richard King established the breadth of the subject area and highlighted its importance. In his monograph Aristotle on Life and Death, King explores the last part of Aristotle’s Parva Naturalia, namely the part that deals with topics such as the length of life, youth, old age, life, death and respiration, which he sees as a continuation and completion of the discussion of the nutritive soul and its activities that began in De Anima. King analyses Aristotle’s conception of life-cycle, stressing the indispensability of nutrition in passing through each stage of a living body’s life-cycle, and the role of the nutritive soul as the efficient cause for growth and decay.

Nevertheless, reports of empirical observations about a wide variety of physical manifestations and states such as Aristotle’s reasonably give rise to ontological questions regarding the ‘identity’ of the nutritive soul and its relation to the soul as a whole: What kind of entity is this nutritive soul? By means of what criteria did the ancients (or, perhaps we as interpreters?) distinguish this psychic part from other psychic parts, and why should this part be thought of as ‘the lowest’? Should we speak of a part-whole relationship between the nutritive part and the rest of the psychê (cf. Perler 2015, p. 11 – 14)? Published in 2012, Thomas Johansen’s The Powers of Aristotle’s Soul offers a systematic analysis of de An. in which a chapter is devoted to nutrition and its importance in Aristotle’s theory of the soul. In Johansen’s own words, “Aristotle gives priority to nutritive soul in his account of the soul because nutrition serves as a paradigm of how the soul works as the nature of living beings. The nutritive soul thus has a special status among the capacities of the soul by illustrating how the soul works so as to bring about life” (p. 119). If indeed for Aristotle the nutritive soul holds a prominent place among the other psychic capacities, ought we not to reformulate our understanding of what it means for it to be ‘the lowest’ part of the soul? In any case, we hope that the collective effort undertaken for the present volume, oriented as it is towards investigating the subjects of nutrition and nutritive soul in Aristotle and Aristotelianism, will help readers explore more fully Aristotle’s and his heirs’ conception of the ‘nature’ of living things, and will give a new impetus to the study of Aristotelian psychology.

2 Philosophers and Physicians on Soul, Life and Nutrition

While the fact that the soul exists and somehow distinguishes a living thing from a non-living one has almost never been truly disputed, what the soul really is and how it activates the body have been hotly debated since antiquity. In the Homeric poems, a person’s soul is often described as being the last breath that leaves his body at the moment of death. In Presocratic thought the soul, either immortal or mortal, is usually held to be of a material nature, being associated for example with air by Anaximenes and Diogenes of Apollonia, and with fire by Heraclitus and Democritus. Later, in Plato we find the view that the soul, though incorporeal, is imprisoned in and can be affected by the body as long as the latter is physically alive, whereas in Aristotle we learn that nous comes “from outside” (θύραθεν), even though the soul is a unified entity. Aristotle frequently attacks his predecessors for their materialistic accounts of the soul. If we also bear in mind that for Plato (a) the soul runs the danger of being affected by one’s struggle to gratify bodily desires, which explains why one should rather abstain from the so-called pleasures connected with food and drink, from sexual pleasures, and from the pleasures of ornament (Phaedo 64d); and (b) the third part of the soul, the appetitive part, is better depicted as a wild beast that must remain tied up and be...