author={Sergei N. Art{\"e}mov},
  journal={The Review of Symbolic Logic},
  pages={477 - 513}
We describe a general logical framework, Justification Logic, for reasoning about epistemic justification. Justification Logic is based on classical propositional logic augmented by justification assertions t: F that read t is a justification for F. Justification Logic absorbs basic principles originating from both mainstream epistemology and the mathematical theory of proofs. It contributes to the studies of the well-known Justified True Belief vs. Knowledge problem. We state a general… 

A Logic for Reasoning about Justified Uncertain Beliefs

A possibilistic justification logic is introduced, its syntax and semantics are presented, and its meta-properties, such as soundness, completeness, and realizability are investigated.

Possibilistic Justification Logic

A possibilistic justification logic is introduced, its syntax and semantics are presented, and its metaproperties, such as soundness, completeness, and realizability are investigated.

Justified Terminological Reasoning

  • T. Studer
  • Philosophy, Computer Science
    Ershov Memorial Conference
  • 2011
A justification logic over the description logic $\mathcal{JALC}$ is introduced and it is shown that this logic satisfies the so-called internalization property stating that it internalizes its own notion of proof.

Justifications for common knowledge

A multi-agent justification logic with evidence terms for individual agents as well as for common knowledge is developed, and a Kripke-style semantics that is similar to Fitting's semantics for the Logic of Proofs LP is defined.

TR-2008014: Why Do We Need Justification Logic?

It is argued that modal language fails to fully represent the epistemic closure principle whereas Justification Logic provides its adequate formalization.

A Note on Strong Axiomatization of Gödel Justification Logic

The canonical possible-world semantics for Justification Logic is extended to this fuzzy realm by considering fuzzy accessibility- and evaluation-functions evaluated over the minimum t-norm and strong completeness theorems for various fuzzy analogies of prominent extensions for basic Justification logic are established.


A system of propositional logic is proposed for reasoning about justification, truthmaking, and the connection between justifiers and truthmakers, exploiting the intuition that justifiers provide epistemic grounds for propositions to be considered true, while truthmakers provide ontological grounds for proposition to be true.

A temporal logic of epistemic and normative justifications, with an application to the Protagoras paradox

The Protagoras versus Euathlus paradox is formalized in this logic and a precise analysis of the paradox is presented, and also briefly discuss Leibniz’s solution.

A logic of defeasible argumentation: Constructing arguments in justification logic

This paper defines a new justification logic that relies on operational semantics for default logic and develops a semantics for “defeaters”: conflicting reasons forming a basis to doubt the original conclusion or to believe an opposite statement.

Epistemic Modeling with Justifications

It is argued that JEM can be applied to a range of epistemic scenarios in CS, AI, Game Theory, etc. and made the case that formal epistemology should venture, when needed, beyond modal logic limits.



Introducing Justification into Epistemic Logic

This paper studies two basic systems, S4LP and S4LPN, of epistemic logic with justification, and shows completeness with respect to natural epistemic semantics, which augments Kripke models with a natural Fitting-style treatment of justification assertions t:F.

On epistemic logic with justification

It is suggested an epistemic semantics which augments Kripke models with a natural Fitting-style treatment of justification assertions t:F, and some new specific properties of basic systems of epistemic logic with justification are established.

Complexity issues in justification logic

Justification Logic is an emerging field that studies provability, knowledge, and belief via explicit proofs or justifications that are part of the language. There exist many justification logics

Logic of knowledge with justifications from the provability perspective.

This paper builds two systems of logic of knowledge with justifications: LPS4, which is an extension of the basic epistemic logic S4 by an appropriate calculus of evidences corresponding to the logic of proofs LP together with the principle that justification implies knowledge, and LPS 4 i , which is L PS4 augmented by the mixed implicit/explicit negative introspection principle.

Logical Omniscience Via Proof Complexity

The usual epistemic modal logics are logically omniscient (modulo some common complexity assumptions) and LOT is applied to evidence-based knowledge systems, which, along with the usual knowledge operator Ki(F) (‘agent iknows F’), contain evidence assertions t:F (“t is a justification for F”).

Justified common knowledge

Multi-agent Explicit Knowledge

An appropriate formalization of the intended semantics is found and it is proved the completeness of these logics with respect to both symbolic and arithmetical models.

Symmetric Logic of Proofs

This paper introduces an extension of the Logic of Proofs, SLP, which incorporates natural properties of the standard proof predicate in Peano Arithmetic, and shows that SLP produces Brouwer-Heyting-Kolmogorov proofs with a rich structure that can be useful for applications in epistemic logic and other areas.

Belief, Awareness, and Limited Reasoning.

Belief, Awareness, and Limited Reasoning: Preliminary Report

In these logics, the set of beliefs of an agent does not necessarily contain all valid formulas, which makes them more suitable than traditional logics for modelling beliefs of humans (or machines) with limited reasoning capabilities.