EDITOR: Dascal, Marcelo
TITLE: G.W. Leibniz, The Art of Controversies
SERIES: The New Synthese Historical Library
Anne Reboul, Pragmatics and cognition team, L2C2, CNRS
Gottfried Wilhelm Leibniz (1646-1716) was a polymath, the inventor of the
calculus independently from Newton, a jurist, a theologian, a philosopher, a
metaphysician. He even published a book on the origins of language. He lived in
the aftermath of the thirty years war, which, though it developed on political
motives, began as a religious war between Protestants and Catholics and which
ended two years after his birth having ravaged Germany (which was one of the
main battle theaters) to such an extent that the population of the German states
was reduced by about 30%. As a protestant living for most of his live in Hanover
where he held different official posts before falling, toward the end of life,
in disfavor, Leibniz took a lively interest in the possibility of reconciling
the different Christian churches through productive controversies and tried to
develop tools for controversies which could be accepted by any rational party to
such a debate. The papers gathered in the present book bear testimony to this
ambition. Though they are fairly heterogeneous, ranging from correspondence to
memos for the political authorities in Hanover, they all speak to one facet or
another of this endeavor to reduce the schism in Christendom. That the attempt
did not, in the end, come to anything does not detract from the interest of
Leibniz's views on what, more generally, makes for productive rather than purely
antagonistic controversy, and contemporary debates, whether political,
religious, academic or whatever, could do much worse than rely on the guidelines
which Leibniz tried to produce.
The present book, edited by Marcelo Dascal (with the help of Quintin Racionero
and Adelino Cardoso), gathers texts, some of which had not been published before
in English, of different origins, from correspondence to papers, including first
drafts, which all bear, directly or less directly on controversy in law or
religion, outlining either external guidelines for the organization of a
controversy (for instance, the presence of a ''judge of controversies''), as well
as indications for the behavior of individual participants, e.g. techniques of
persuasion, logics, etc.
The book opens with an introductory essay which gives the needed background,
regarding both Leibniz's personality and the reason why he was interested in
controversy, usefully contrasting his ambition (trying to secure a
reconciliation between the Protestant and Catholic churches) with that of Locke,
who was - less ambitiously - content to accept the schism, but was trying to
ensure political and legal tolerance between the different creeds (see Locke
1689). It briefly outlines some of the solutions which Leibniz proposed for the
setting of controversies between antagonist parties.
The main part of the book is composed of chapters of varying sizes corresponding
to different texts by Leibniz, each of which is accompanied by a short scholarly
introduction, indicating the origin and nature (letter, memo, etc.) of the text,
its original language (Latin, French or German), as well as its relation to
other texts by Leibniz or other authors. Additionally, each text comes with a
complete apparatus of footnotes (concerned with additions or corrections by
Leibniz, textual matters) and endnotes, giving the biographical or conceptual
information necessary for text comprehension.
Chapter 1, ''Vices of mingled disputes'', endeavors to set guidelines for
rationally resolving controversies. It advocates the necessity of a ''director''
which would ''referee'' the controversy, weighing arguments, rather than merely
Chapter 2, ''The controversy of controversies'', outlines a ''model of rationality''
for the solution of various controversies, notably religious ones, discussing
the relative importance of reason on the one hand and textual norm (from
religious texts, e.g. the Bible) on the other, rejecting the additions made to
the sacred texts by, e.g. the catholic tradition. In passing, Leibniz discusses
the epistemic question of how one can believe in the ''approval of propositions
that are not understood'' (13), a problem which is now currently revived through
the notion of semantic deference in philosophy of language. In cases where there
is no sure procedure towards truth, a ''judge of controversies'' is needed, who
should rely, to disentangle the issues, on a few formal techniques, for the
discovery of which Leibniz gives some suggestions.
Chapter 3, ''The religion of a peasant'', elaborates the notion of a ''judge of
controversies'', who should not judge the conclusions themselves, but rather
weigh the arguments adduced by the parties.
Chapter 4, ''The elements of thinking'', defends dialogue as the surest way toward
the determination of the provability or truth of a proposition, outlining
different notions such as ''reasoning'', ''convincing'' and ''demonstrating''.
In chapter 5, ''The balance of law'', deals with a ''logic of the contingent'',
which Leibniz sees as the mainstay of juridical practices, though of course also
relevant out of law.
Chapter 6, ''Can there be an obligation to believe?'', defends the Lutherian
position according to which faith is ''a divine gift'', i.e. not obligatory,
against the Catholic position that faith is rationally necessary. One of the
interests of this text lies in its explicitness: Leibniz in fact proposes a
logical demonstration, going from a few definitions (of ''obligation'', ''believe'',
etc.) to the effect that ''There is no obligation to believe, but only to search
with utmost application'' (46), with a corollary which meets Lockean tolerance.
Chapter 7, ''Controversies on sacred matters'', begins with a distinction between
''controversy'', ''trial'', and ''war'', advocating controversy as a means to reach
truth through reason, this being the guiding star of a competent judge of
Chapter 8, ''The judge of controversies'', defends the utility of controversies
(notably in religious matters), though admitting that ''absolutely speaking, no
man is a judge of controversies vis-à-vis another'', given that the judge of
controversies may terminate controversies, in as much as terminating a
controversy means either leading the parties to forget the controversy or
persuading some of them to adopt the position of their opponents.
Chapter 9, ''Towards a heuristic for litigation'', turns towards the law, trying
to lay rules for the avoidance of endless litigations.
Chapter 10, ''The method of jurists and the method of doctors'', defends the
method of medicine in as much as it is a collective and conjectural ''art''.
Chapter 11, ''Interpretation and argumentation in law'', outlines the different
elements that go into the determination of meaning, outlining different
pragmatic factors which combine for a rational interpretation, thus making
possible the application of the law.
Chapter 12, ''Towards a heuristics for discovery'', repudiates the possibility of
purely formal methods of discovery, outlining heuristics for discovery, relying
notably on analysis and synthesis of plural methods, from mathematical and
logical tools, among them the calculus of probabilities, to the exploitation of
Chapter 13, ''Estimating the uncertain'', deals with an important preoccupation of
Leibniz's, i.e. the calculus of probability.
Chapter 14, ''Towards a numerical universal language'', proposes an arithmetic
model of a universal language, in which controversies could be solved by
calculating the ''solution''. This rests on the metaphysical conviction that
''there is nothing which does not submit to number'', arithmetic thus being
''something akin to the statics of the universe, by which the degrees of things
can be examined'' (120).
Chapter 15, ''The encyclopedia and the method of discovery'', comes back to the
topic of discovery, dealing mainly with the collection and organization of all
extent knowledge for the purpose of discovery, advocating the use of tables, the
ordering of propositions as universal or reciprocal, the distinction between
principles, definitions and hypotheses, etc. and proposing a list of the
sciences which should be included (grammar, logic, mnemonics, etc.), where
''science'' is sometimes clearly understood as relating to cognitive functions or
abilities and the means of improving them.
Chapter 16, ''Towards a heuristic for persuading'', turns back to debate and
outlines not only a logic of argumentation, but also an ethics of argumentation.
Chapter 17, ''The other's place'', defends the importance of taking into account
the other's point of view, not only in ethics and politics, but in debate.
Chapter 18, ''Persuading a skeptic'', written under the form of a dialogue between
a skeptic (''skeptic'' designates here the writers who denied the very possibility
of a rational theology) and an anti-skeptic (Leibniz's position). The
anti-skeptic again defends the necessity of taking the other's point of view as
a way of establishing a common ground of agreed-upon propositions from which to
evaluate those that are actually in debate.
Chapter 19, ''On controversies'', formulates a series of measures for the rational
conduct of controversies, relying on moderation, embodied in a ''rapporteur'', who
reformulates the arguments and counter-arguments of the parties, with a view to
making them clearer and thus more easy to judge as to their validity and
relevance to the question in debate.
Chapter 20, ''On principles'', defends the two principles of non-contradiction and
of the existence of the perceived.
Chapter 21, ''Two prefaces to the general science'', gathers two texts, the first
a diagnosis of the dire state of knowledge in Leibniz's time, seen as a
heterogeneous and disorderly pile of scattered opinions and facts, the second
outlining a synopsis for a book which would present the whole of knowledge in a
useful and orderly fashion, allowing both for solutions to scientific
controversies and for further discoveries.
Chapter 22, ''Introduction to a secret encyclopedia'', gives general principles
and notions (''concept'', ''complex'', etc.) for the ordering of knowledge.
Chapter 23, ''On the creation of a new logic'', deals with inferences as a way to
Chapter 24, ''New openings'', comes back to the possibility of a ''general
science'', which would be linked to mathematics through the science of
probabilities, bridging the gap between empiric and non-empiric knowledge.
Chapter 25, ''Theology and the principle of contradiction'', defends the
possibility of a rational theology (based on the principle of contradiction)
against Honoré Fabri, a Jesuit who claimed that God was not bound by this
principle. Leibniz points out that this destroys any possibility of identifying
heretics or atheists and of a rational theology.
Chapter 26, ''Changing religion'', identifies formally the positions and
differences between Catholics and Protestants, outlining where the burden of the
proof applies on either side.
Chapter 27, ''Methods of reunion'', deals with the possible reunion of the
Christian churches, debating both the political problems linked with asymmetries
in status, power, etc. and the way to put into practice the balance of reason,
by taking into account the different views of the contenders.
Chapter 28, ''An ars characteristica for the rational sciences'', defends the
application of rationality outside of numerical abilities, to the ars
characteristica (the delimitations of notions) which could solve controversies,
through proportional weights of different reasons.
Chapter 29, '''Characterizing' definitions and demonstrating propositions''
returns to the same subject, the establishment of definitions allowing for
Chapter 30, ''Advancing the art of discovery'', deals with the extension of
mathematical demonstrations to non mathematical or logical domains, advocating
the use of synthesis until it can be transformed into analysis.
Chapter 31, ''Correspondence with the Hamburg Jungians'' - where ''Jungians'' refers
to the disciples of Joachim Jungius, a logician -, deals with an assorted group
of subjects, from probabilities to the conceptual simplification of legal notions.
Chapter 32, ''The philosophical sin controversy'', takes place in a controversy
between the Jesuit college of Dijon and Arnauld about the notion of a
''philosophical sin'', i.e. a sin against rationality. Leibniz takes the example
of ignorance as a stepping stone for the discussion of the controversy.
Chapter 33, ''Confronting the Catholic hardliners: Two memoirs for Pellisson'', is
a commentary over a text by Pellisson on the religious controversy between
Catholics and Protestants, followed by a reply to Pellisson's reply on the first
Chapter 34, ''Defining what pertains to faith'', deals with what should or should
not be considered as pertaining to faith (and thus subject to the Church's
Chapter 35, ''Judgment of a catholic doctor'', is a direct contribution to the
religious controversy at a time when the hope for a reunification of Christian
churches ran high.
Chapter 36, ''Presumptions and fictions in legal argumentation: correspondence
with Johannes Werlhof'', discusses the legal status of possession of land.
Chapter 37, ''The 'method of establishments''', draws a distinction, on the model
of mathematics, between what is certain and what is uncertain and between what
is discovered and what has to be discovered. This, supplemented by
probabilities, would contribute to the improvement of knowledge.
Chapter 38, ''The achievements of logic and beyond'', defends a broad view and
application of logic and logical methods.
Chapter 39, ''Facts, contracts, and natural laws'', deals with the juridical
matter of so-called ''Natural Law'', and of whether the law should play any role
Chapter 40, ''Approaching the church of England'', defends the possibility of a
reunification of the Christian churches, and outlines rules for debates.
Chapter 41, ''Dialectic principles and their application'', discusses the argument
of an incompatibility between the existence of God and the existence of evil,
supposedly leading to a non rational theology. Against that view, Leibniz
dialectically defends the compatibility between the existence of both God and evil.
Chapter 42, ''The history and tasks of logic: To Cornelius Dietrich Koch'',
presents a broad view of a history of logic.
Chapter 43, ''Bold conjectures: To Louis Bourguet'', advocates a formal approach
to the choice between different cosmological hypotheses.
Chapter 44, ''The dynamics of formulating and expounding the system: to
Nicolas-François Remond'', outlines a metaphysical text which Leibniz probably
never got to write.
Chapter 45, ''The use of logic against skepticism: to Karl G. Ehler'', defends the
use of logic as the ''judge of controversies''.
This book is an invaluable contribution to the history of (philosophical) ideas
and also a contribution to the pragmatics of discussion and debate, including
argumentation (in the vernacular sense) and logic. This is hardly surprising
given the continuing intellectual eminence of Leibniz. In making accessible
Leibniz's writings on controversies, debates and, more generally, intellectual
disputes, whatever their subject matters, Dascal gives the reader an important
opportunity to discover or to improve his or her knowledge of 17th and 18th
century thought, as well as his or her own view of how the use of language can
contribute to the solution of controversies. The critical apparatus is wide and
complete and the reader is never left in ignorance of relevant facts. The only
criticism which could be made is the chronological rather than thematic ordering
of the chapters, which means that the reader has to go back and forth between
chapters to achieve a coherent view of Leibniz's position (and the evolution of
that position through time) on this or that subject.
This, however, remains a minor criticism and the book should be read by
philosophers of language (as well as historians of philosophy) as well as by
pragmaticians and more generally by those who are concerned by the standards of
Locke, J. (1689) A letter concerning toleration, http://manybooks.net/.
Anne Reboul is a Senior Researcher at the French Center for Scientific Research
(CNRS) in France. She has a Ph.D. in Linguistics (EHESS, Paris) and a Ph.D. in
philosophy (University of Geneva, Switzerland). She has written some books,
among which is an _Encyclopedic Dictionary of Pragmatics_, and quite a few
papers in French and English on pragmatics and/or philosophic subjects. She has
developed an interest in recent years in both language evolution and animal
cognition and communication and has recently published a book on Language and
human cognition. She has been an admirer of Leibniz (notably of his approach to
conditionals and conditional reasoning) for years.