Chapter 2 How to Study Later Medieval Theories?

In: Animal Rationality
Anselm Oelze
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The present book focuses on later medieval theories, more precisely, the theories of authors who lived and worked at some point between roughly 1250 and 1350. The main reason for concentrating on this period is that it is characterised by a comparatively large amount of discussion about animal cognition in general and animal rationality in particular. One of the pivotal driving forces behind this was the transmission Aristotle’s writings in the Latin West. Although it had begun much earlier, the translation of decisive parts of the Corpus Aristotelicum had not been completed before the second half of the thirteenth century. This body of work contains two major collections of books that are relevant in the present context (see Chapter 4). First, there is the so-called ‘Books on Natural Philosophy’ (libri naturales). Among these are the Physics as well as the highly influential treatise On the soul (De anima). Moreover, they include a number of ‘Little Treatises on Natural Philosophy’, especially psychology and physiology, known as Parva naturalia. The second relevant collection, the ‘Books on Animals’ (De animalibus libri), unites at least three zoological treatises: the ‘History of Animals’ (Historia animalium), ‘On the Parts of Animals’ (De partibus animalium), and ‘On the Generation of Animals’ (De generatione animalium). Together these collections fuelled the discussion on animals’ cognitive capacities because commenting on Aristotle’s works belonged to the principal tasks of (late) medieval academics.

There was, of course, also a discussion on animal rationality before this commentary tradition began to flourish in the Latin West. One of the most interesting figures in this respect is Adelard of Bath. 1 In his Questiones naturales, written during the first half of the twelfth century, he develops an interesting and quite original account of the nature and capacities of animal souls. 2 Undoubtedly, his interest in this topic arose from the far-reaching “discovery of nature” in the twelfth century (see Chapter 4). However, unlike thirteenth- and fourteenth-century theories, Adelard’s account is not connected to the Aristotelian model of the soul. Just as little is it influenced by the so-called theory of inner senses. In its most influential form, this theory was developed before the thirteenth- and fourteenth centuries and outside the Latin West, especially by Avicenna. It is more than just the passive reception of Aristotle’s psychology and very likely became as influential as it did in later centuries because it provided solutions to some of the problems produced by Aristotle’s model of the soul. 3 Therefore, the influence of (earlier) medieval Arabic psychology and zoology cannot be ignored in a study of later medieval Latin theories of animal rationality. 4

The setting of these theories was not restricted to commentaries on Aristotle. There are also many other sources in which one can find relevant contributions. These include, for instance, theological Summae and Sentences commentaries. They differ from commentaries on Aristotle with regard to content and function. Nonetheless, they must receive some attention in this context because later medieval theories of animal rationality are patchwork rather than all of a piece. This is illustrated by the fact that there is not a single medieval treatise on this subject. Rather, the question of animal cognition in general and of animal rationality in particular came up in very different kinds of texts, many of which do not, prima facie, seem to be concerned with these topics. But since nonhuman animals often functioned as a sort of heuristic tool in the Middle Ages (see Chapter 4), the discussion on their capacities was not limited to one particular genre but spread across various texts and disciplines which is why any reconstruction of late medieval theories of animal rationality must rely on various sources.

The sources of the present study are basically of two different kinds. The majority are texts which exist in critical Latin editions, such as many of the commentaries on Aristotle’s De anima or Peter Lombard’s Sentences. Some of these texts have already been translated into English or other European languages, either partly or entirely. 5 This also applies to some texts for which only uncritical Latin editions are available, such as Albertus Magnus’ comprehensive De animalibus. The second type of source are those texts which have not yet been edited and are only available in early prints or manuscripts. A good example is Pseudo-Peter of Spain’s commentary on De animalibus which, so far, has received only very little attention. 6 These kinds of sources will not be used as extensively as sources of the first type but they will be used in order to establish a relatively broad basis which will help to show that there was not just one, but a whole spectrum of arguments and explanations in the later medieval period.

Despite the variety of sources, the present book does not aim to prepare a complete map of the theoretical landscape in the later Middle Ages. Instead, it aims to philosophically reconstruct, analyse, evaluate, and compare a wide range of views on four aspects of this problem: (1) universal cognition and concept formation, (2) judging, (3) reasoning, and (4) prudence (see Chapter 3 more below). Such a systematic approach does, of course, bear the risk of ignoring many aspects. For much could be said about the institutional context or the theological background of medieval theories. Yet, the advantage of this kind of approach is that it can deliver interesting philosophical insights into a historical discussion. This does not mean that we are to ignore its historical peculiarities. There are, of course, many significant differences between past and present theories of animal rationality, but there are also many astonishing parallels.

These continuities and discontinuities will be fleshed out by discussing the views of more than ten late medieval thinkers, namely, Albertus Magnus, Roger Bacon, Pseudo-Peter of Spain, Bonaventure, Thomas Aquinas, Giles of Rome, Peter of John Olivi, John Duns Scotus, William of Ockham, Gregory of Rimini, Adam Wodeham, John Buridan, and Nicole Oresme. 7 Some of these figures have already been widely read and studied, while relatively little is known about others. Moreover, some of them were Dominicans, others were Franciscans, and some were not affiliated with a particular order at all. Still, all of them did, to differing degrees, participate in the academic life of their time, mainly at Oxford and Paris. They were trained in philosophy and theology, commented Aristotle’s writings as well as those of other authoritative figures, and all of them developed interesting – and different – views on various questions concerning animal rationality. This is an important finding, insofar as all of them subscribed to the metaphysical premise according to which only human animals are endowed with intellect and reason. That is, from a common starting-point they went in divergent directions, and the aim of this book is to track their paths.

Tracking their paths does not, however, require one to write a history of the development of their theories. Whether the views of the early Ockham or the early Aquinas accord with those of the late Ockham or the late Aquinas is not the primary concern here. Just as little is the aim to examine whether there is a notable difference between the theories from the beginning of the second half of the thirteenth and those from the end of the first half of the fourteenth century. Instead, the aim is to depict the variety of theories that existed between 1250 and 1350. So far, only very little attention has been paid to this variety because the denial of reason to animals did not seem to leave many theoretical options open. That this assumption needs to be revised is the main thesis of this book.


On Adelard as natural philosopher see Burnett (1987) and Grant (2007), 117–122. On his account of animal rationality see Roling (2011), 228f.


See Adelard of Bath, Questiones naturales, qq. 13–14, ed. Burnett (1998), 110–118. Another original and perhaps even slightly earlier text that has recently been edited is Ralph of Battle, De nesciente et sciente, lib. i, c. 4, §§37–76, eds. Niskanen & Goebel (2015), 258–279.


For a general overview of animals in Islamic philosophy and theology see Lauzi (2012), Wannenmacher (2017), and Adamson (forthcoming). On particular issues and authors see, for instance, Kruk (1995), (1997), (2001), and (2002); López-Farjeat (2010), (2012), and (2016); Druart (2016).


Unless otherwise indicated, all translations in this study are mine.


I am grateful to Theodor W. Köhler for providing me with his transcription of this work.


This study’s conception thus follows, for instance, Perler (1992), (2004) and (2011), or Pasnau (1997).

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