The Summa Logicae (Latin, in English it's the Sum of Logic) is a textbook on logic by William of Ockham. There are articles about the Summa Logicae in Wikipedia and in Logicmuseum.

It was published in Paris in 1488. There are different typed variants of this textbook, for example here (in English).

But I can't find any scans or photos of the original handmade manuscript or the original (first) edition. Do you know any links or libraries or museims, where I can find it?

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    Maybe this question fits better into history.se
    – Lukas
    May 10, 2013 at 9:05
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    @Lukas Thank you, I asked a question into history.se. But this is a philosophical work, because of this I asked my question here. May 21, 2013 at 2:26

1 Answer 1


You raise a few points. First ‘Sum of logic’ is the Wikipedia title. Don’t trust anything that Wikipedia says, or at least, be cautious. The book is generally known by its Latin title, Summa Logicae. ‘Summa’ is difficult to translate in English – it doesn’t really mean ‘summary’.

The essay by Peter King that you link to is a short ‘summary’ of the work.

You say: “But I can't find any scans or photos of the original handmade manuscript or the original (first) edition. Do you know any links or libraries or museims, where I can find it?”

Until the 15th century, all such works were published in manuscript (i.e. handwritten) form, so there is no sense in which there was an ‘original first edition’. The concept of an ‘edition’ arrived with printing, when instead of writing a copy, you do a lot of work to set the type and get everything just right, then you publish with a large print run, and keep on printing until you decide on the need for a second edition.

There is also the concept of a ‘critical edition’. Rather than rely on the old 15th century printed works and other editions copied from them, you go back to the original manuscript sources, and compare them together to look for copying errors, with the aim of finding out what the author ‘really’ said. The first critical edition of the Summa was published in 1974 as the first volume of Opera Philosophica (St. Bonaventure, N.Y. Editiones Instituti Franciscani Universitatis S. Bonaventurae, 1974. 899 p., eds Boehner, Philotheus, Gál, Gedeon, Brown, Stephen).

I don’t have the full list of all the ms used for the critical edition, although two of them were: Bruges, Bibl. de la Ville 498 (1340); and Avignon, Bibl. Mun. 1086 (1343). I am not sure you would want these, however, as they will look something like this http://www.logicmuseum.com/w/images/7/77/Worcester_13_32vb_sensu_compositionis.jpg I.e. not just in Latin but in a written form of Latin which is difficult to read without training.

I hope that helps. Personally I would stick to the published translations in English – see below. Note that the whole work has never been fully translated into English, Ockham’s own language.

Loux, Michael J. 1974. Ockham's Theory of Terms: Part I of the Summa Logicae. Notre Dame, Ind.: University of Notre Dame Press. Complete Translation.

Freddoso, Alfred J., and Schuurman, Henry, trans. 1980. Ockham's Theory of Propositions: Part II of the Summa logicae. Notre Dame, Ind.: University of Notre Dame Press.

Longeway, John Lee (2007), Demonstration and Scientific Knowledge in William of Ockham, University of Notre Dame Press, Notre Dame, IN. A translation of Summa Logicae III-II: De Syllogismo Demonstrativo, with selections from the Prologue to the Ordinatio.

  • Thank you. Do you know anything about samples of Ockham's handwriting? Aug 20, 2014 at 6:36
  • We have samples of Duns Scotus's own writing, from his corrections to his 'examined' work. I don't know of any samples of Ockham's own writing. Aug 20, 2014 at 8:58

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