Collaborateurs et recherche
My main research activities are about philosophical logic and metaphysics. I defended my Ph.D. dissertation Existential Dependence and Cognate Notions in November 2002 at the University of Geneva. The dissertation, which I wrote under the supervision of Kevin Mulligan, is one in metaphysics. Its purpose is to elucidate a notion which pervades a large amount of metaphysical writings since Aristotle, to wit the notion of existential dependence. My past research also concerns the logic of essence (logics of essentialist statements introduced by Kit Fine), modal logic (three-valued logics inspired by the work of Arthur Prior), relevance logics (logics of 'analytic containment') and theories of persistence through time. I am currently working on a big project on the theory of essence.
Je travaille actuellement à la rédaction de ma thèse de doctorat sous la direction du Professeur Kevin Mulligan. Mon travail, intitulé 'Memory : An Analysis', consiste à proposer une analyse de la mémoire dans le cadre de la philosophie analytique contemporaine et se divise en deux grandes parties. Dans la première, je discute la nature des états mentaux mnésiques et propose une distinction fondamentale entre souvenirs et croyances acquises dans le passé. Contrairement à de nombreuses analyses contemporaines, j'estime que la mémoire ne doit pas être réduite à la conservation d'un jugement, mais est plus proche de la perception. C'est dans cette perspective que je propose une série de parallèles entre perception et mémoire, en particulier en ce qui concerne la dimension non-conceptuelle de la perception, ainsi que sur le problème des liens entre expérience et objet. Je défends dans cette partie une forme de réalisme direct en ce qui concerne la mémoire. Je travaille également sur la question des démonstratifs mémoriels, sur les liens entre mémoire et causalité, ainsi que sur les différences entre mémoire médiate et immédiate. Les problèmes liés à la pensée temporelle sont aussi au coeur de ma recherche. La seconde partie de mon travail consiste à évaluer le statut épistémique de la mémoire, la possibilité de démontrer sa validité, ainsi que le type de justification qu'il est possible d'accorder aux croyances mnésiques.
I am writing a thesis (under the supervision of Kevin Mulligan) about the exemplfication relation and try to discuss its logic and metaphysics within a broader theory of formal concepts. Apart from this, I'm particularly interested in the following topics: (i) how robust are the properties required in our ontology by the truthmaker argument? (ii) what is the distinction between particulars and universals and between kinds and properties? (iii) what is the status of relations? (iv) do properties fall into kinds and if so, which are the principal kinds of properties and how are they defined? (iv) may mereology be called a "logic" of material things? (v) what are abstract entities and in what sense (if any) may they be said to exist? (vi) what are logical constants? (vii) what is the connection (if any) between exemplification and set-membership and between set-theory and mereology? (viii) what are formal ontological kinds and relations? (ix) do qua objects exist and in what sense are they relata of the exemplification relation? (x) what are the prospects of a reist ontology?
My work at the IRIS-project is mainly concerned with the concept of grounding, i.e. the concept expressed by the connective 'because'. I started by considering the most detailed and thought-through theory of grounding availabe, namely Bernard Bolzano's. In his Wissenschaftslehre (published in 1837) he carefully distinguishes the concept of grounding from the concept of an epistemic reason, the concept of causality and the concept of deducibility (i.e. logical consequence). Against the background of these distinctions I critically discussed Bolzano's positive account of grounding by reconstructing it in axiomatic form. I then investigated whether and to what extent Gerhard Gentzen's theory of normal proof can be regarded as providing a formal theory of the way especially logical truths are grounded.
As a member of Iris, I worked for my doctoral thesis (which I submitted in 2002). The thesis has three major parts, focussing on three ontological categories. In part 1, I examine the category of shareable properties (universals), in part 2 I turn to the category of particularised properties (tropes), and in the final part I treat the category of substance. My inquiry is most of the time conceptual. Thus I examine into the conceptual resources of everyday talk about properties and tropes, paying much attention to linguistic data relevant to these issues. Finally, I discuss the classic idea that substances enjoy a certain kind of ontological independence. I develop an account of independence in terms of conceptual explanatory relations, and show the priority of concepts of substances to concepts of other categories.
My interests include metaphysics, metaethics, philosophy of language and philosophy of mind. More in particular: (i) In metaphysics I am interested in the notion of a response-dependent property. I claim that the class divides into rigid response-dependent properties, which are dispositions to produce certain mental responses in certain rigidly specified subjects under certain rigidly specified conditions, and hence are real although less than fully objective properties, on the one hand, and flexible response-dependent properties, which are properties, in an abundant sense, whose extensions track those of different dispositions or their bases, and hence do not support realism. (ii) In metaethics, I favor an antirealist, relativistic, conception of evaluative properties, and try to respond to various objections. (iii) In philosophy of language, I try to elaborate a simple proposal concerning rigity for predicates: roughly predicates that signify the same property across worlds, and defend it from a trivialization problem and an over-generalization problem. (iv) In philosophy of mind, I am inclined to favor a representationalist conception of phenomenal experience, and am interested in the possibility of combining it with a dispositional theory of properties like colors.
I am writing a thesis about the epistemology of Bernard Bolzano which will contain 3 main parts: 1) An outline of Bolzanos theory of judgment with special emphasis on the notion of "Zuversicht" (Confidence). It is in this notion that converge Bolzanos ideas about subjective and epistemic probability. A parallel main subject: the relation between causality involved in judgments and the truth of their content. 2) Discussion of the difficulties arising from Bolzanos theory of representations and the causal account he gives of the existence and function of intuitions (Anschauungen). A coherent notion of intuition involves Bolzanos ontology of substances and souls, as well as his theory of perception. The two domains are linked by the concept of force which is a key concept to understand the relations between causality and deducibility/explication (Ableitbarkeit/Abfolge). 3) Bolzanos heuristics: finding truths and generating knowledge, or the distinction between "finden" and "erfinden". The empirical basis of logical knowledge; a deductivist's "feeling for truth", his trust in common sense and "social roads to knowledge".
My research concerns the concept of truth, both in its semantic and extra-semantic dimension. Currently, I am writing a doctoral thesis entitled 'Meinong's Theory of Truth.' In this work I will try to reconstruct Meinong's theory of truth and assess the results of this reconstruction from the point of view of the present developments in the field of philosophical semantics and truth theory. Such a study of Meinong's epistemological views does not exist so far in the philosophical literature, even though Meinong's ideas can be shown to be interesting not only from a historical perspective, or because of the influence that Meinong's works have exerted upon analytic philosophy. Most studies of Meinong's philosophy concentrate on ontological issues and they are often accompanied by providing a logical system of so called Meinongian logic. The epistemological problems are raised rarely and primarily in the light of historical considerations. The thesis, although an attempt at a faithful reconstruction of Meinong's truth theory, will not be historically oriented in principle. It will also try to uncover the present implications of the surprisingly modern intuitions of this old-fashioned philosopher for some questions currently discussed within philosophical truth theory, epistemology and semantics.
The problem I am going to face in my doctoral thesis is to determine the truth conditions of a sentence like 'S believes that p'. If we accept the propositionalist theory of meaning, a possible and easy solution of this problem will be: 'S believes that p' expresses a 2-place belief relation between a subject S and the Russellian proposition that p. For example, "Tom believes that Cicero is bald" means something as B(Tom, [Cicero, baldness]). Nevertheless, if in this sentence (let's suppose it is true) we substitute the name 'Cicero' with 'Tully', we will obtain a true sentence even in the case that Tom, on reflection, is disposed to sincerely assert "Tully is not bald"; then the so-called Disquotation principle fails. In order to preserve this principle, it could be held the sentence "Tom believes that Tully is not bald" is true too. But if we substitute 'Tully' with 'Cicero', we will obtain a true sentence which, joined to "Tom believes that Cicero is bald", violates the so-called Consistency principle (according to this principle, any sentence like 'S believes that p and S believes that not p', where the subject S is rational, is necessarily false).
Many philosophers hold these problems can be solved by adding to the Russellian propositions new (abstract or linguistic or mental) entities called modes of presentation or by replacing the Russellian propositions with new propositions composed by modes of presentation. It could be demonstrated most theories which use modes of presentations are not able to respect Disquotation principle and Consistency principle, and the remainders are very counter-intuitive.
In a recent paper of mine, which is entitled "Assertions and Individuals", I propose a version of Russellian theory which have not this kind of problems. In my opinion, a subject is related with a singular proposition only if he is directly in contact with the object his belief is about. Since - I hold - a subject is not ever directly in contact with a whole individual but only with some parts of his, the singular proposition expressed, for example, by the sentence "Cicero is bald" in belief context doesn't contain the individual Cicero but rather a part of Cicero Tom is directly in contact with; similarly, "Tully is not bald" in belief context expresses a singular proposition containing another part of Cicero Tom is directly in contact with but Tom doesn't realize this part and the other one are parts of the same individual. It could be demonstrated that my proposal is able to preserve Disquotation and Consistency principles.
The title of my doctoral theses is 'Zusammengesetztheit und Realismus' (Complexity and Realism). The main aim is to disclose the hidden or forgotten link between the logical and the ontological complexity. Unfortunately there is no or little interest in the modern logic to investigate the relation of part and whole. The modern theory of part and whole, known under such names as Mereology or Calculus of Individuals, was unfortunately elaborated under a strong influence of ontological purism, known as Nominalism and Antiinfinitivism or Monism. Nevertheless there are other ways how to set up a theory of arrangements, which do not suffer from ontological restrictions. This way has in fact a rich tradition, e.g. Leibniz or Bolzano. In the modern times there are other two realistic systems of part and whole, the system of Parts by Peter Simons and the theory of complexes based on the Transparent Intensional Logic by Pavel Tichy´. I want to give a brief survey of the main features of logic like analyticity, reasoning, truth predicate, reference and counterfactuals as based on a general theory of complexity, whereby general means that the same sort of complexity should cover the concrete, the abstract, the contingent and the logical objects as well.
The Grammar of Being -- If one takes a realist stance on language and reality, one endorses the contention that the categorial structure of the world is reflected, in one way or another, in a universal semantics of natural language. This assumption has been vindicated in the last decade by linguistic research into the logical structure of natural language sentences. Indeed, inspired by a proposal of Davidson (1980a), Parsons's (1990) investigations into the 'subatomic' semantics of English phrases have revealed that the complementation of verbs and adjectives can be conveniently interpreted on the basis of a hidden quantification over events and states. A rigorous enquiry in the metaphysical implications of an event-based semantics for natural language would seem to be profitable in two respects. On the one hand, an account of how things participate in events involves dealing with almost all basic ontological problems that have to be tackled by any comprehensive metaphysical theory. In this sense, Parsons's 'subatomic semantics' cries out for a thorough ontological clarification, notably for a careful evaluation of the metaphysical choices as to treating the problem of identity through mereological and qualitative change as well as explaining the various ways of persistence in time, namely endurance vs. perdurance. Such an appraisal has to be based on a solid theory of objects and properties and requires equally fundamental decisions as to the axiomatisation of mereology, topology, as well as the theory of dependence. Furthermore, I will show that Parsons?s classification of thematic roles can be refined by taking into account the presence or absence of a causal dependence between participant and event, as well as the distinction between persons and mere bodies, respectively that between mental and physical occurrences. Thus an event-based semantics for natural language seemingly has to be grounded on a comprehensive ontology as a general theory of real-world categories.
On the other hand, it is obvious that the application of the conceptual tools offered by a metaphysical theory to the semantical analysis of natural language sentences represents a most convenient way to validate and to refine ontological definitions and theorems. Though real falsifications or corroborations are probably too much to hope for, the usefulness of an ontology in formulating a scientific theory of linguistic meaning comes very near to an empirical criterion (if there ever can be such a thing) for adopting or rejecting metaphysical claims.
I'm writing my Doctoral Thesis (under the supervision of Kevin Mulligan) about the similarity relation. I'm investigating formal approaches of the relation in order to account for degrees of similarity and comparative similarity. With such a treatment I Hope to offer a close discussion on topics such as: Counterparthood; analogy and induction; similarity of meaning; Metaphor; Truthlikeness. I'm also particularly interested in the following Topics: logic and metaphysic of relations, the special composition question, Modal Realism, analysis of reduction.
My research interests are primarily in ontology (formal ontology and
spatiotemporal ontology), comparative ontology (and metaontology), and the
formalization of ontological theories. Topics of special interest include:
modes of being in time and persistence, the concept of location (in space and
time), universals, and relations. The last topic is also that of my doctoral
work with Kevin Mulligan. It is mostly about the metaphysics of relations
- I regard that as formal ontology - and it is a bit about their logic.
It also brings about some considerations in few material domains.
My research interests include ontology, philosophy of logic, aesthetics, value theory and the history of Austrian Philosophy. In particular, I am interested in the concepts of existence and reference.
I defended a Master Thesis on the ontology and logic of fictitious objects and was working on the ontology of art and on "Reference, Quantification and Ontological Commitment" dealing, among other things, with the relationship between existence and quantification, reference and truth, logic and natural languages.
Currently, I am working on problems with (allegedly) "nonexistent objects", such as fictitious objects (like Sherlock Holmes and Pegasus), past and future objects, nonexistent objects of intentional states (like fear, imagination or desire) or such "Meinongian objects" as the golden mountain and the round square.
The pivotal questions are: Is it necessary to assume that there are nonexistent objects in order to explain the consistency of various kinds of (non-philosophical) discourse? If so, which kinds of nonexistent objects have to be assumed? Can all kinds of discourse about the allegedly nonexistent be explained by the assumption that there are nonexistent objects? If not, how are these kinds of discourse to be explained?
My working hypothesis is that there are no nonexistent objects in the literary sense (i.e., objects that do not exist), but that there are some kinds of unreal objects (where "unreal" means neither physical nor mental). However, it is more than doubtful whether the assumption of unreal objects can explain all kinds of discourse that is allegedly about something nonexistent. In particular, this holds for discourse about the past and the future.
Mon activité de recherche a été jusqu'à ce jour essentiellement consacrée à la philosophie des mathématiques et de la logique. Il portait sur les questions de signification du langage des mathématiques constructives en rendant compte autant que possible de leur diversité ; tant d'un point de vue historique (de l'intuitionnisme à l'informatique théorique) que technique (différentes approches sémantiques - algébrique, topologiques, récursives - sont envisagées) et aussi, et surtout, philosophique (de l'activité mathématique sans langage de Brouwer à la théorie de la signification de Dummett, Prawitz et Martin-Löf). Actuellement je m'intéresse toujours à ce thème, mais dans un contexte historique, philosophique et technique élargi aux logiques dites sous-structurelles, d'une part, et à la logique classique, d'autre part.