To what extent do keas, Nestor notabilis , learn from each other? We tested eighteen captive keas, New Zealand parrots, in a tool use task involving visual feature discrimination and social learning. The keas were presented with two adjacent tubes, each containing a physically distinct baited platform. One platform could be collapsed by insertion of a block into the tube to release the bait; the other platform could not be collapsed. In contrast to birds that acted on their own (“individual (...) learners“), birds that could observe a demonstrator bird operated the collapsible platform first. However, they soon changed their behaviour to inserting blocks indiscriminately in either tube. When we reversed the collapsibility of the platforms, only adult observers but neither their demonstrators that had individually learnt nor the juveniles immediately altered their former preference. Observers, however, did not simply reverse their initial preference but rather moved to and then stayed at a chance performance as to where to insert a block first. In conclusion, the keas' overt exploration soon overrode the effect of social learning. We argue that such behaviour might help keas to find more efficient extractive foraging techniques in their native variable, low-risk environment. Keywords: tool use behaviour; social learning; reversal learning; physical cognition. (shrink)

Ramsey et al.'s article provides a more sensitive framework for comparative innovation than others' operationalisations have done. Nevertheless, a methodology has to be elaborated in order to determine to what degree a behaviour is novel. Psychological processes have to be considered when evaluating the value of reference groups and in order to figure out where to look for innovation.

This paper argues for two principal conclusions about natural language semantics based on John Buridan's considerations concerning the notion of formal consequence, that is, formally valid inference. (1) Natural languages are essentially semantically closed, yet they do not have to be on that account inconsistent. (2) Natural language semantics has to be token based, as a matter of principle. The paper investigates the Buridanian considerations leading to these conclusions, and considers some obviously emerging objections to the Buridanian approach.

This paper argues that three characteristic modern positions concerning intentionality – namely, (1) that intentionality is ‘the mark of the mental’; (2) that intentionality concerns a specific type of objects having intentional inexistence; and (3) that intentionality somehow defies logic – are just three ‘modern myths’ that medieval philosophers, from whom the modern notion supposedly originated, would definitely reject.

We study the process of observation (measurement), within the framework of a “perspectival” (“relational,” “relative state”) version of the modal interpretation of quantum mechanics. We show that if we assume certain features of discreteness and determinism in the operation of the measuring device (which could be a part of the observer's nerve system), this gives rise to classical characteristics of the observed properties, in the first place to spatial localization. We investigate to what extent semi-classical behavior of the object system (...) itself (as opposed to the observational system) is needed for the emergence of classicality. Decoherence is an essential element in the mechanism of observation that we assume, but it turns out that in our approach no environment-induced decoherence on the level of the object system is required for the emergence of classical properties. (shrink)

(Appeared in: J. Bernard-J. Kelemen: Zeichen, Denken, Praxis , Institut fur Sozio-Semiotische Studien: Vienna, 1990, pp. 249-267. To print the published version, click here.).

`Realism', `conceptualism' and `nominalism' are terms that one is most likely to come across in history of philosophy textbooks, presented as ones labeling three major ontological alternatives provided by mediaeval philosophy. The general inadequacy of these labels is perhaps best shown by the desperate efforts to provide further, modified labels , the well-known `moderate' and `extreme' or `exaggerated' versions of the above, in hopes of implying at least a lesser amount of falsehood in hanging..

"This question, and others, asking about the number of predicates, or of the predicables, or of the categories, or of natural principles, or the elements, etc. are rather difficult and tedious, especially for youngsters, for whom one should explain the logical and sophistic cavils which the more advanced students [need] no longer care about. Therefore, for the sake of freshmen, I posit some easy and [somewhat] facetious conclusions". (p. 183, ll. 2203-2209.).

Common representational content allows the Buridanian classification of human concepts discussed in the fourth chapter, which provides the first thoroughgoing, systematic survey of Buridan’s conception of a mental language. The chapter discusses the divisions of concepts into syncategorematic and categorematic, simple and complex, absolute and connotative, and singular and common concepts. Besides presenting these classifications, the chapter provides a detailed discussion of the idea of conceptual complexity as semantic compositionality, its role in Buridan’s nominalist program of “ontological reduction,” and his (...) precarious positioning of his account of the distinction between the representational contents of universal and singular concepts “somewhere between” those of Ockham and Aquinas. The discussion relates the emerging issues to contemporary concerns in the philosophy of mind and language, such as the possibility of forming genuinely singular concepts and simple substantial concepts that would allow some terms of our language to function as rigid designators; the differences between consciousness and mental content; and the problem of universal representation without real universals. (shrink)

Buridan's life, works, and influence -- Buridan's logic and the medieval logical tradition -- The primacy of mental language -- The various kinds of concepts and the idea of a mental language -- Natural language and the idea of a formal syntax in Buridan -- Existential import and the square of opposition -- Ontological commitment -- The properties of terms (proprietates terminorum) -- The semantics of propositions -- Logical validity in a token-based, semantically closed logic -- The possibility of scientific (...) knowledge -- Buridan's anti-skepticism -- Buridan's essentialist nominalism. (shrink)

“The expression ‘free logic’ is an abbreviation for the phrase ‘free of existence assumptions with respect to its terms, general and singular’.”1 Classical quantification theory is not a free logic in this sense, as its standard formulations commonly assume that every singular term in every model is assigned a referent, an element of the universe of discourse. Indeed, since singular terms include not only singular constants, but also variables2, standard quantification theory may be regarded as involving even the assumption of (...) the existence of the values of its variables, in accordance with Quine’s famous dictum: “to be is to be the value of a variable”. (shrink)

Is Aquinas a representationalist or a direct realist? Max Herrera’s (and, for that matter, Claude Panaccio’s) qualified answers to each alternative show that the real significance of the question is not that if we answer it, then we can finally learn under which classification Aquinas should fall, but rather that upon considering it we can learn something about the intricacies of the question itself. In these comments I will first argue that the Averroistic notion of “intentional transfer”, combined with the (...) Avicennean idea of the indifference of nature, yielding the Thomistic doctrine of the formal unity of the knower and the known renders the question moot with regard to Aquinas, indeed, with regard to the pre-modern epistemological tradition in general. These considerations will then lead to a number of further, both historical and philosophical questions, which I will offer in the end for further discussion. (shrink)

Saint Anselm’s proof for God’s existence in his Proslogion, as the label “ontological” retrospectively hung on it indicates, is usually treated as involving some sophisticated problem of, or a much less sophisticated tampering with, the concept of existence. In this paper I intend to approach Saint Anselm’s reasoning from a somewhat different angle.

Summary: The aim of this paper is to explore the relationships between Buridan’s logic and the ontology of modes modi). Modes, not considered to be really distinct from absolute entities, could serve to reduce the ontological commitment of the theory of the categories, and thus they were to become ubiquitous in this role in late medieval and early modern philosophy. After a brief analysis of the most basic argument for the real distinction between entities of several categories (“the argument from (...) separability”), I point out that despite nominalist charges to the contrary, “older realists”—that is, authors working before and around Ockham’s time—were not committed to such real distinctions, and thus to an overpopulated ontology, by their.. (shrink)

The final chapter provides a summary account of Buridan’s essentialist nominalism, showing how Buridan can successfully claim to be both a nominalist denying the existence of real shared essences and an essentialist endorsing the possibility of discovering truly essential attributes of things, which allows valid scientific generalizations. The concluding critical part of the chapter, however, points out a fundamental conflict between Buridan’s abstractionist cognitive psychology of absolute concepts and his logical semantics of the corresponding absolute terms that grounds his nominalist (...) essentialism. (shrink)

The fifth chapter provides a detailed discussion of Buridan’s strategy of identifying the conceptual structures discussed in the chapter 4 by means of the various “syntactical clues” provided by spoken and written natural languages. The chapter compares the Buridanian strategy of “regimentation” with the modern strategy of formalization, and argues that for the purposes of a “natural logic” the former is not inferior to the latter. But in order to bridge the conceptual gap between the two approaches, the chapter also (...) discusses a simple extension of standard quantification theory that is capable of faithfully representing a large part of Buridan’s logic. Indeed, the chapter argues that the resulting formal system is in accord not only with Buridan’s logic, but with our natural language intuitions in general, providing more faithful representation of natural language reasoning than standard quantification theory. (shrink)

cannot, cover the broad topic indicated in the title. Rather, it will concern itself only with some preliminary ideas leading the way to a larger project, which, however, should eventually bear an even broader title. As a matter of fact, here I will consider at some length only two authors from the beginning of the period indicated in the title, namely, Aquinas and Siger of Brabant. (Or perhaps three authors, provided the anonymous author of the..

This chapter continues the discussion of the issues raised by the chapter 6, focusing on the issue of ontological commitment. The chapter argues that Buridan’s theory of ampliation, reconstructed in terms of quantification with restricted variables, provides a genuine third alternative to the opposing modern views of Quine and “the Meinongians.” Furthermore, the chapter argues that Buridan’s theory thus reconstructed says “all the right things” according to Quine in its object-language; however, it still seems to side with the Meinongians in (...) its meta-language. However, this is just a feature of the reconstruction: “the real Buridan” does not have this distinction, but works out his natural language semantics under conditions of what Tarski described as “semantic closure.”. (shrink)

This paper confronts a certain modern view of the relation between semantics and ontology with that of the late-medieval nominalist philosophers, William Ockham and John Buridan. The modern view in question is characterized in terms of what is called here “the thesis of onto-semantic parallelism,” which states that the primitive (indefinable) categorematic concepts of our semantics mark out the primary entities in reality. The paper argues that, despite some apparently plausible misinterpretations to the contrary, the late-medieval nominalist program of “ontological (...) reduction” was not driven by considerations that try to “read off” ontology from semantic analysis or those that try to identify semantic primitives in their search for ontological primitives. The medieval authors presented a much more flexible, dynamic view of “Aristotelian naturalism,” which challenges both of the unappealing modern alternatives of “conceptual tribalism” and “conceptual imperialism.”. (shrink)

This chapter contains sections titled: The author of the Summulae The Summulae and the realism of Peter of Spain.

In these comments I am going to argue that Yiwei Zheng's paper, by postulating an imaginary mental language in a proposed new interpretation of Ockham's conception of mental language, provides us with an imaginary solution to what turns out to be an imaginary problem. Having said this, however, I hasten to add that the paper has undeniable merits in pointing us in the right direction for revealing the imaginary character of the problem.

Is there a grammar of the name ‘God’? In an obvious and trivial sense there certainly is. This term, being a part of the English language, has to obey the grammatical rules of that language. So, for example, by consulting the relevant textbooks and dictionaries we can establish that ‘God’ is a noun, so it can function as the subject or predicate of simple categorical sentences, but it cannot, for example, function as a verb or a preposition.

In this paper, I will primarily argue for the consistency of Aquinas’ conception, according to which the human soul, uniquely in God’s creation, is both the inherent, material, substantial form of the human body, and the subsistent immaterial substance underlying the immaterial operations of its immaterial, rational powers, namely, intellect and will. In this discussion, I will point out that typical challenges to Aquinas’ conception usually rely on semantic or ontological assumptions that can plausibly be denied in Aquinas’ own conceptual (...) framework. Since the issue of consistency merely assumes the less than self-evident claim of the immateriality of the human intellect, I will also provide a brief sketch of what I take to be Aquinas’ most promising proof of this claim. (shrink)

Anthony Kenny's book is one of the best of its genre, exemplifying the kind of introduction into (some field of) Aquinas's thought that endeavors to make his ideas accessible to the philosophically interested contemporary reader in terms of such philosophical, scientific and everyday concepts with which the reader can safely be assumed to be familiar. Indeed, Kenny's book provides us with such a good example of this genre that it brings into sharp focus the problems of the genre itself. Therefore, (...) while duly acknowledging the book's virtues of clarity of presentation, and its highly readable, almost conversational style, let me concentrate in this brief review on this problematic aspect of Kenny's book, as someone who is just as much concerned with making Aquinas accessible to a contemporary audience as the author is. (shrink)

This paper presents John Buridan’s nominalist ontology of habits, as the acquired qualities of innate powers aiding or hampering their operations, against the background of a more traditional interpretation of Aristotle’s doctrine to be found in Boethius, Albert the Great, Thomas Aquinas, and Cajetan. The paper argues that considerations of his late question commentary on Aristotle’s Nicomachean Ethics may have forced Buridan to rethink some of his earlier arguments for his parsimonious nominalist ontology of powers endorsed in such earlier works (...) as his Questions on Aristotle’s Categories and De anima. The lesson to be drawn from this investigation seems to be that upon working out the details of a nominalist programme in such fields as moral psychology and ethics, the requisite refinements sooner or later will involve such modifications of an originally “radical” programme that would bring it closer to what used to be the “mainstream” view. Even so, this much seems enough further down the line to change significantly how issues are framed relative to the “mainstream” view as well. (shrink)

This paper analyses the import of three claims extracted from Geach's works concerning theories of predication and the reference of common terms, the notions of being or existence, and the force/content distinction and theories of valid inference, respectively. The paper highlights the theoretical and historical errors involved in these claims as well as their enormous influence and inspiration in the field of the philosophical study of medieval logic and metaphysics.

This paper argues in the first place that nominalists are right in insisting against ontological realists that semantic universality does not require commitment to universal entities. However, Ockham, in his zeal to get rid of Scotus’s universal entities, swept under the carpet the issue of universal representational content of genuinely universal symbols, conflating it with the mere indifference of the information content of non-distinctive singular representations. Buridan did come up with an abstractionist theory of the formation of genuinely universal representational (...) content to solve the resulting issues, however, the paper argues further, his solution is committed to attributing the sort of “aspectuality” to universal absolute concepts that his Ockhamist semantics denies to them. The conclusion of the paper suggests how Aquinas’s “moderate realism” can provide a consistent solution without the ontological extravaganza of ontological realists, without conflating the mere indifference of singular representation with genuine universality, and without having to deny aspectuality to our quidditative universal concepts formed by abstraction. (shrink)

To many contemporary philosophers, the phrase “essentialist nominalism” may appear to be an oxymoron. After all, essentialism is the doctrine that things come in natural kinds characterized by their essential properties, on account of some common nature or essence they share. But nominalism is precisely the denial of the existence, indeed, the very possibility of such shared essences. Nevertheless, despite the intuitions of such contemporary philosophers,2 John Buridan was not only a thoroughgoing nominalist, as is well-known, but also a staunch (...) defender of a strong essentialist doctrine against certain skeptics of his time. But then the question inevitably arises: could he consistently maintain such a doctrine? (shrink)

This paper argues that Aquinas's conception of the human soul and intellect offers a consistent alternative to the dilemma of materialism and post-Cartesian dualism. It also argues that in their own theoretical context, Aquinas' arguments for the materiality of the human soul and immateriality of the intellect provide a strong justification of his position. However, that theoretical context is rather "alien" to ours in contemporary philosophy. The conclusion of the paper will point in the direction of what can be done (...) to render Aquinas's position more palatable to contemporary philosophers. (shrink)

Contemporary "essentialism", if we want to provide a succinct, yet sufficiently rigorous characterization, may be summarized in the thesis that some common terms are rigid designators. [1] By the quotation marks I intend to indicate that I regard this as a somewhat improper (though, of course, permitted) usage of the term (after all, nomina significant ad placitum [2]). In contrast to this, essentialism, properly so-called, is the Aristotelian doctrine summarizable in the thesis--as we shall see, no less rigorous in its (...) own theoretical context--that things have essences. (shrink)

After a brief analysis of the specifics of teleological explanations as opposed to causal explanations, the paper seeks to establish the irreducibility of the former to the latter by arguing that teleological explanations are inextricably tied to our notion of intentionality. Since this result undermines the very possibility of “a physicalist reduction” of the explanation of teleological phenomena, especially of human beha- vior, the rest of the paper develops an argument against the perceived need of any such reduction. According to (...) the conclusion of the paper, a more promising program is the development of a “modern, scientific Aristotelianism”, one that can provide a consistent conceptual framework that accommodates both types of explanation. (shrink)