Reflections on Paraconsistency
June 25, Full Day & June 26, Morning

Workshop at UNILOG'2018 organized by

Franca D'Agostini
(University of Milan, Italy)

Elena Ficara
(Paderborn University, Germany)

Paraconsistent logics form a lively sector of the discipline we call Philosophical Logic. The idea that contradictions are – in some cases or in some way – acceptable without «explosion» of our rational systems has been developed by paraconsistent logicians also with reference to epistemological and metaphysical implications, and there is a wide literature on the theme. However, the arising of contradictions, and the need of coming to terms with them, has also ethical, political and more generally practical implications that sometimes fade into the background.

Not only that, one of the main problem of paraconsistency (but this is true also of other fields, like modal logic) is that on the one hand there are philosophically oriented works with a weak or no technical part and vice versa: some technical paraconsistent works have no consideration for the philosophical aspects of the theme.

One aim of our workshop is thus to promote interaction between technical and non-technical works in the field. A second but not secondary aim is to enlarge the view, involving people interested in contradictions, but not exclusively as militant logicians.

We thus encourage contributions able to suggest and treat preliminary questions, sometimes underrated or not extensively studied by logicians, such as

1. In metaphysical and truth-theoretic perspective:
- A contradiction is the joined occurrence of two states of affairs that in principle cannot jointly occur: what do we mean by ‘joint occurrence’ in this case?
- Are there contradictory truthmakers? If there are, are they to be intended as two overlapping facts, or only one fact?
- If the acceptance of contradictions is ruled by truth (as dialetheists hold), can we really renounce the classical exclusive notion of ‘T’, in virtue of which if ‘p’ is true then ‘not p’ must be false?

2. In epistemological perspective:
- Do we really believe the unbelievable?
- What kinds of epistemic gluts are rationally acceptable?

3. In ethical and generally practical perspective: - Disagreements and dilemmas are typical contexts in which the occurring of contradictions has political consequences: how can we use the theories of paraconsistent logicians to deal with these occurrences? - Is Orwell’s analysis of the contradictory language of power (the newspeak) still appropriate, nowadays, face to the positive «explosion» of communication produced by our «information era»?

4. In meta-theoretical perspective:
- Why do we study contradictions? What normative conclusions can be drawn from our theoretical efforts on this issue?
- What can we learn from the history of paraconsistency?
- Is ‘philosophy’ as such the enterprise that aims at solving or interpreting contradictions, as many authors in the tradition held (see Hegel or Wittgenstein)?

Call for papers

We invite contributions on all aspects of paraconsistency and contradiction. Topics include:

  • paraconsistent systems: respective costs and benefits
  • gaps, gluts, and other truth values
  • what's so bad about trivialism?
  • contradictory truthmakers
  • the unbelievable: its role and believability
  • contradictions, discussive conflicts, and dilemmas
  • paradoxes in logic and elsewhere
  • what can the historical treatments of contradictions (in Aristotle, Pascal, Hegel, Bergson, etc.) still teach us?
  • was Hegel paraconsistentist?
  • what was really Aristotle's attitude toward contradictions?
  • old and new theories about the square of oppositions
  • the philosophical relevance of dialetheism and of other paraconsistent views
  • the political relevance of the philosophy of contradiction

    Abstracts (one page) should be sent by November 15, 2017 via e-mail to: 


    !!! This schedule is subject to change until the last minute !!!

    Keynote Speakers

    Jonas Becker Arenhart, UFSC, Florianópolis, Brazil, “Material exclusion, contradictions and other oppositions”

    Graham Priest, City University of New York, USA, “It Was So Revolting I Couldn't Take my Eyes Off It”

    María del Rosario, UNAM, Mexico City, Mexico, “Contradiction, triviality, inconsistency toleration and other misunderstandings in the empirical sciences”

    Roy Sorensen, Washington University St Louis, USA, “Ill-Defined Attitudes”

    Contributing Speakers

    Jonas R. Becker Arenhart, and Ederson Safra Melo, Department of Philosophy, Federal University of Santa Catarina, Brazil and Department of Philosophy, Federal University of Maranhãao, Brazil, “(De)motivating Gluts”

    Hakob Barseghyan, Institute for the History and Philosophy of Science and Technology, University of Toronto, Canada, “The Role of Paraconsistency in Scientific Change”

    Gregory Carneiro, Department of Philosophy, University of Brasília, Brazil, “A paraconsistent approach to da Costa's deontic logic: beyond contradictions and triviality”

    Ebubekir Muhammed Deniz, Istanbul 29 Mayis University, Istanbul, Turkey, “On the Possibility of Dialetheic Metaphysics”

    Peter Eldridge-Smith, School of Humanities, Australian National University, Centre for Strategic Business Studies, Australia, “Paradoxes, Hypodoxes, Hypodox-paradox duality and Hypodoxical Paradoxes”

    Ben Martin, Queen's University, Kingston, Canada, “What is a Contradiction?”

    Manuel A.Martins and Diana Costa, Department of Mathematics, University of Aveiro, Portugal, “How to Compose Programs in Belnapian Dynamic Logic?”

    Adam Trybus, Institute of Philosophy, University of Zielona Góra, Poland, “Paraconsistency meets refutation: a case of maximality”

    Max Urchs, University of Business and Law, Wiesbaden, Germany, “Reasoning about Complexity Needs Reflections on Paraconsistency”

    Katherine Valde, Philosophy Department, Boston University, USA, “On the Possibility of Metaphysical Dialetheism”

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