Susanne Bobzien (born 1960) is a German-born philosopherWho'sWho in America 2012, 64th Edition whose research interests focus on philosophy of logic and language, determinism and freedom, and ancient philosophy.Bobzien's British Academy Page
/ref> She is currently a visiting research fellow at

Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...

and professor emerita and a quondam fellow at

Oxford University The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the second-oldest continuously operating u ...

and All Souls College, Oxford.

Early life

Bobzien was born in

Hamburg Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...

, Germany, in 1960. She graduated in 1985 with an M.A. at Bonn University, and in 1993 with a doctorate in philosophy (D.Phil.) at

, where from 1987 to 1989 she was affiliated with Somerville College.

Academic career

Bobzien was a tutorial fellow in philosophy at

Balliol College, Oxford Balliol College () is a constituent college of the University of Oxford. Founded in 1263 by nobleman John I de Balliol, it has a claim to be the oldest college in Oxford and the English-speaking world. With a governing body of a master and aro ...

from 1989 to 1990, fellow and praelector in philosophy at The Queen's College, Oxford from 1990 to 2002, and CUF Lecturer in Philosophy at Oxford University from 1993 to 2002. She was appointed to a senior professorship in philosophy at Yale in 2001Yale Daily News 3/23/2001, "Philosophy hires rising Oxford star"
and held this position from 2002 to 2010. From 2013 to 2023, she was Professor of Philosophy and Senior Research Fellow at All Souls College, Oxford. In the fall of 2023 she resigned her fellowship and returned to the US for family reasons, where in 2024 she took up a visiting professorship at

. Since 2025, she has been a visiting research fellow in the Department of Philosophy at

. Among her awards are a British Academy Research Readership (2000–2002),British Academy Research Readerships 2000–2002.
/ref> and a fellowship of the National Endowment for the Humanities (2008–09).
/ref> In 2014 she was elected a

Fellow of the British Academy Fellowship of the British Academy (post-nominal letters FBA) is an award granted by the British Academy to leading academics for their distinction in the humanities and social sciences. The categories are: # Fellows – scholars resident in t ...

, the United Kingdom's

national academy A national academy is an organizational body, usually operating with state financial support and approval, that co-ordinates scholarly research activities and standards for academic disciplines, and serves as a public policy advisors, research ...

for the humanities and social sciences. In 2021, she was elected a corresponding member of the International Academy of Philosophy of Science. Bobzien has published several books and numerous articles in leading academic journals and collections.

Philosophical work

Determinism and freedom

Bobzien's major work ''Determinism and Freedom in Stoic Philosophy'' is "the first full-scale modern study of the toictheory f determinism.Times Literary Supplement (15 September 2000) "Chrysippus and the seamless web" "It explores ... the views of the Stoics on causality, fate, the modalities, divination, rational agency, the non-futility of action, moral responsibility, nd theformation of character".Mind 109 (2000) p. 855 In this book and in her articles "The Inadvertent Conception and Late Birth of the Free-Will Problem" and "Did Epicurus discover the Free-Will Problem?" Bobzien argues that the problem of determinism and free-will, as conceived in contemporary philosophy, was not considered by Aristotle, Epicurus or the Stoics, as was previously thought, but only in the 2nd century CE, as the result of a conflation of Stoic and Aristotelian theory.PhilPapers archive link to Bobzien's professional papers
/ref> Bobzien's "Die Kategorien der Freiheit bei Kant" (The Categories of Freedom in Kant) has been described as an article "that has long been the starting point for any German reader seeking to deepen his understanding of the second chapter of the Analytic of Kant's Critique of Practical Reason." It differentiates the main functions of Kant's Categories of Freedom: as conditions of the possibility for actions (i) to be free, (ii) to be comprehensible as free and (iii) to be morally evaluated.Notre Dame Philosophical Reviews, 2010.11.06, of K. Ameriks, O. Höffe (eds.) Kant's Moral and Legal Philosophy, Cambridge 2009.
/ref>

History of logic

Bobzien's ''Die stoische Modallogik''Die stoische Modallogik (Würzburg 1986) is the first monograph on Stoic modal logic.K. Hülser, ''Die Fragmente zur Dialektik der Stoiker'', vol. 3. p. VI. In her paper "Stoic Syllogistic" Bobzien sets out the evidence for Stoic syllogistic. She argues that this should not be assimilated into standard propositional calculus, but treated as a distinct system which bears important similarities to relevance logic and connexive logic.Review of Oxford Studies in Ancient Philosophy XIV, 1996. In "Stoic Sequent Logic and Proof Theory", she argues that stoic deduction resembles backward proof search for Gentzen-style substructural sequent logics as developed in structural proof theory,''History and Philosophy of Logic'' 2019.
/ref> and in the co-authored "Stoic Logic and Multiple Generality" she lays out evidence that Stoic logic could handle the problem of multiple generality in a variable-free first-order logic.''Philosophers' Imprint'' 2020.
/ref> Bobzien's paper "The Development of Modus Ponens in Antiquity" traces the earliest development of

modus ponens In propositional logic, (; MP), also known as (), implication elimination, or affirming the antecedent, is a deductive argument form and rule of inference. It can be summarized as "''P'' implies ''Q.'' ''P'' is true. Therefore, ''Q'' must ...

(or Law of Detachment).PhilPapers
/ref>The Development of Modus Ponens in Antiquity", ''Phronesis'' 47, 2002
/ref> She has also reconstructed the ancient history of hypothetical syllogisms''Phronesis'' 45, 2002, 87–137.
/ref> and Galen's representation of peripatetic hypothetical syllogistic, and shown these differ from stoic syllogistic and contemporary propositional logic.''Rhizai Journal for Ancient Philosophy and Science'' 2, 2004, 57–102. In the 2021 extended essay "Frege plagiarized the Stoics", based on her 2016 Keeling Lecture, Bobzien argues in detail that Frege plagiarized them on a large scale in his work on the philosophy of logic and language, written mainly between 1890 and his death in 1925.''Themes in Plato, Aristotle, and Hellenistic Philosophy: Keeling Lectures 2011-18''
London: 2020.

Vagueness and paradoxes

Bobzien has worked on the philosophical application of the

modal logic Modal logic is a kind of logic used to represent statements about Modality (natural language), necessity and possibility. In philosophy and related fields it is used as a tool for understanding concepts such as knowledge, obligation, and causality ...

S4.1 to vagueness and paradoxes. She has introduced and developed the philosophical ideas of columnar higher-order vagueness, borderline nestings, and semi-determinability.Mormann, ''Erkenntnis'' 2020.
/ref>''Analytic Philosophy'' 2013.
/ref>''Notre Dame Philosophical Review''.
/ref> In "Gestalt Shifts in the Liar", presented in he
2017 Jacobsen Lecture
Bobzien analyses three features of liar sentences and shows how their combination leads to the liar's paradoxicality: salience-based bistability, context sensitivity, and assessment sensitivity. On this basis she proposes the modal logic S4.1 as governing the truth operator and offers a revenge-free solution to the liar paradox that relates to Herzberger's revision theory of truth. Bobzien has proposed a logic of higher-order vagueness (the quantified modal logic S4.1 supplemented with Max Cresswell's Finality Axiom) that delivers a generic solution to the Sorites paradox and avoids higher-order vagueness paradoxes and sharp boundaries.''Philosophers' Imprint'' 2010
/ref>''Aristotelian Society Suppl.'' 89, 2015.
/ref> The proposed logic is weaker than

classical logic Classical logic (or standard logic) or Frege–Russell logic is the intensively studied and most widely used class of deductive logic. Classical logic has had much influence on analytic philosophy. Characteristics Each logical system in this c ...

and stronger than

intuitionistic logic Intuitionistic logic, sometimes more generally called constructive logic, refers to systems of symbolic logic that differ from the systems used for classical logic by more closely mirroring the notion of constructive proof. In particular, systems ...

. It is a modal companion to the superintuitionistic logic QH+KF.Bobzien Faculty Page
/ref>

Selected publications

Determinism and freedom
and Freedom in Stoic Philosophy''
(Oxford 1998).
''Freedom, and Moral Responsibility: Essays in Ancient Philosophy''
(Oxford 2021). *"The Inadvertent Conception and Late Birth of the Free-Will Problem" (''Phronesis'' 43, 1998) *"Did Epicurus Discover the Free-Will Problem?" (''Oxford Studies in Ancient Philosophy'' 19, 2000) *"Die Kategorien der Freiheit bei Kant" (in ''Kant: Analysen-Probleme-Kritik'' vol. 1, Würzburg, 1988) History of logic *''Die stoische Modallogik'' (Würzburg 1986). *''Alexander of Aphrodisias: On Aristotle Prior Analytics 1.1-7'', with J. Barnes, K. Flannery, K. Ierodiakonou (London 1991). *"Stoic Syllogistic" (''Oxford Studies in Ancient Philosophy'' 14, 1996). *"The Development of Modus Ponens in Antiquity" (''Phronesis'' 47, 2002)
"Stoic Sequent Logic and Proof Theory"
(''History and Philosophy of Logic'' 40, 2019)
"Stoic Logic and Multiple Generality"
with Simon Shogry (''Philosophers' Imprint'' 20, 2020)
"Frege Plagiarized the Stoics"
(in ''Themes in Plato, Aristotle, and Hellenistic Philosophy: Keeling Lectures 2011-18'', London 2021) Vagueness and paradoxes
"Higher-order Vagueness, Radical Unclarity, and Absolute Agnosticism"
(''Philosophers' Imprint'' 10, 2010)
"In Defense of True Higher-Order Vagueness"
(''Synthese'' 180, 2011)
"If it's Clear, then it's Clear that it's Clear, or is it? – Higher-Order Vagueness and the S4 Axiom"
(Oxford 2012)
"Higher-Order Vagueness and Borderline Nestings – a Persistent Confusion"
(''Analytic Philosophy'' 54.1, 2013).
"Columnar Higher-order Vagueness or Vagueness is Higher-Order Vagueness"
(''Aristotelian Society Suppl.'' 89, 2015)
"Gestalt Shifts in the Liar or Why KT4M is the Logic of Semantic Modalities"
(in ''Reflections on the Liar'', Oxford 2017)
"Intuitionism and the Modal Logic of Vagueness"
with Ian Rumfitt (''Journal of Philosophical Logic'' 49, 2020)
"A Generic Solution to the Sorites Paradox"
(''Erkenntnis'', 2024)

References

External links

*
Homepage at All Souls College, OxfordPage at PhilPeopleWomen in Logic
{{DEFAULTSORT:Bobzien, Susanne 20th-century British philosophers 20th-century German philosophers 21st-century British philosophers 21st-century German philosophers Yale University faculty German scholars of ancient Greek philosophy Philosophers of language German women philosophers Living people 1960 births Fellows of the British Academy Fellows of All Souls College, Oxford Alumni of Somerville College, Oxford 20th-century German women