Dear Colleagues,

We would like to bring to your attention a newly published special issue 
on the topics of Unification and Coherence. The aim of the special issue 
is to bring together scholars who work on the topics of unification 
and/or coherence in the hope of fostering research at the intersection 
of these two intimately related fields.

Unification and Coherence
Theoria: An International Journal for Theory, History and Foundations of 
Science
Vol. 30, No. 1, pp. 7-114.
Edited by Ioannis Votsis and Gerhard Schurz
http://www.ehu.eus/ojs/index.php/THEORIA/issue/view/1308

Contributions by:
Victor Gijsbers
Michael Schippers
Jonah N. Schupbach
Gerhard Schurz
Mark Siebel
Ioannis Votsis

Major themes explored include: measures of coherence, measures of 
unification, coherence and inconsistency, coherence and ceteris paribus 
conditions, coherence and understanding, causality and unification, 
unification and confirmation.

Table of Contents:

‘Introduction’ (pp. 7-9).
Ioannis Votsis and Gerhard Schurz

‘Inconsistency as a Touchstone for Coherence Measures’ (pp. 11-41)
Mark Siebel and Michael Schippers
Abstract: The debate on probabilistic measures of coherence has focused 
on evaluating sets of consistent propositions. In this paper we draw 
attention to the largely neglected question of whether such measures 
concur with intuitions on test cases involving inconsistent propositions 
and whether they satisfy general adequacy constraints on coherence and 
inconsistency. While it turns out that, for the vast majority of 
measures in their original shape, this question must be answered in the 
negative, we show that it is possible to adapt many of them in order to 
improve their performance.

‘The Possibility of Coherentism and the Stringency of Ceteris Paribus 
Conditions’ (pp. 43-52)
Jonah N. Schupbach
Abstract: Schupbach (2008) puts forward a "possibility result" for 
Bayesian Coherentism, showing that there exist plausible sets of ceteris 
paribus conditions that imply that coherence is truth-conducive. Against 
this result, Schubert (2012) has argued that Schupbach's considered 
ceteris paribus conditions are "jointly inconsistent". In this article, 
I first show that Schubert's attempted proof of this claim is 
fallacious, and hence that the possibility result still stands. Next, I 
consider a related criticism of Schupbach's result, inspired by Olsson's 
(2005) constraints on ceteris paribus conditions. This leads to a 
general discussion of the principle(s) that should guide one in choosing 
such conditions.

‘Is a coherence theory of understanding possible?’ (pp. 53-71)
Victor Gijsbers
Abstract: Coherence is a measure of how much our beliefs hang together. 
Understanding is achieved when we see that something is not just a 
brute, isolated fact. This suggests that it might be possible to develop 
a coherence theory of understanding, which is what we attempt to do in 
this article using several formal measures of coherence. However, it 
turns out that a coherence theory runs into trouble with the asymmetry 
of understanding. We identify four difficulties and give suggestions for 
how they could be solved. These solutions all point away from coherence 
and towards a rather different notion, unification, which casts some 
(though not conclusive) doubt on the possibility of a coherence theory 
of understanding.

‘Causality and Unification: How Causality Unifies Statistical 
Regularities’ (pp. 73-95)
Gerhard Schurz
Abstract: Two key ideas of scientific explanation - explanations as 
causal information and explanation as unification - have frequently been 
set into mutual opposition.  This paper proposes a "dialectical 
solution" to this conflict, by arguing that causal explanations are 
preferable to non-causal explanations because they lead to a higher 
degree of unification at the level of the explanation of statistical 
regularities. The core axioms of the theory of causal nets (TC) are 
justified because they give the best if not the only unifying 
explanation of two statistical phenomena: screening off and linking up. 
Alternative explanation attempts are discussed and it is shown why they 
don't work. It is demonstrated that not the core of TC but extended 
versions of TC have empirical content, by means of which they can 
generate independently testable predictions.

‘Unification: Not Just a Thing of Beauty’ (pp. 97-114)
Ioannis Votsis
Abstract: We often hear that simplicity, explanatory power and 
unification, though aesthetically pleasing or beautiful qualities, are 
at best pragmatic considerations in matters of choosing between rival 
hypotheses. This paper aims to offer a novel conception and an 
associated measure of unification, both of which are demonstrably more 
than just pragmatic considerations. The discussion departs from a brief 
survey of some failed attempts to carve out adequate conceptions of 
unification. It then proceeds to an analysis of the notions of 
confirmational connectedness and disconnectedness. Roughly speaking, 
these notions attempt to capture the way support propagates or fails to 
propagate between the content parts of a hypothesis or, equivalently, 
between the contents of two or more hypotheses. The two notions are 
instrumental in helping to tackle the problem of ad hoc, and in 
particular monstrous, hypotheses. More importantly for the purposes of 
this paper, they are essential ingredients in the proposed conception of 
unification and its associated measure. In simple terms, the more the 
content of a hypothesis (or, equivalently, the content of a set of 
hypotheses) is confirmationally connected the more that content is 
unified. Since the confirmational connectedness of two content parts is 
determined by purely objective matters of fact, the proposed notion and 
measure of unification are themselves strictly objective, i.e. not 
merely pragmatic considerations in matters of hypothesis choice.

Best wishes,
Ioannis Votsis

-------------------------------------
Dr. Ioannis Votsis
http://www.votsis.org

Senior Lecturer, New College of the Humanities
19 Bedford Square, London WC1B 3HH
United Kingdom
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https://www.nchum.org/faculty/philosophy-ba

Assistant Director & Research Fellow
Düsseldorf Center for Logic and Philosophy of Science
Philosophy Institute
Heinrich-Heine-Universität Düsseldorf
Universitätsstraße 1, Geb. 24.52/01.23
D40225 Düsseldorf
Germany

Tel: +49 211 81-11602
Fax: +49 211 81-11750
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