This is the clearest way Thomas Aquinas’s Summa Theologiæ* is to be cited in academic writing. There seems to be no authoritative answer. This does not mean, however, that there are no wrong ways to do so. The following seems reasonable and very clear.
Citing the Summa is based on its structure, so let’s begin with that.
The Summa has three main divisions called Parts:
- Part I (Prima Pars) deals with God
- Part II (Prima / Secunda Secundæ) deals with Humanity and Morals
- Part III (Tertia Pars) deals with Christ
- Part I has 119 Questions
- Part II is divided into two parts:
- The First Part of Part II has 114 Questions
- The Second Part of Part II has 189 Questions
- Part III has 99 Questions
- The issue of the article is given in the form a question.
- Several plausible responses are listed.
- A contrary response (reflecting Thomas’s thinking) from some authority is cited (the sed contra – “On the contrary”).
- Arguments are given for Thomas’s response (the respondeo – “I answer that”).
- Brief replies are given to objections based on the initial responses (the adversus – “Objections”).
- Part number
- First Part: “I” or “Ia”
- First Part of Second Part: “I-II” or “Ia-IIæ”
- Second Part of the Second Part: “II-II” or “IIa-IIæ”
- Third Part: “III” or “IIIa”
- **Supplement: “Suppl.” or “Suppl. IIIae”
- Question number
- Article number
- If it is a Reply to an objection, abbreviate adversus as “ad” followed by its number
- Sum I-II, 2, ii, ad. 1.
- ST I-II, Q. 3, Art. 2, ad. 1.
- ST I-II, Q 3, A 2, ad. 1.
- S.T. I-II, 2, ii, a.1.
- Ia.I: 19, 34, 193(53)
- Ia. 3, 2 ad 3.
- 2a2ae. 180, 10. 3a 35, 8.
- * The title of Aquinas’s work is Summa Theologiæ (Lt. for “Summary of Theology”), but it is sometimes titled Summa Theologica (e.g.,NewAdvent.com and the popular Benziger Brothers 1947 translation). If you are not referencing a translation with “Theologica” in the title, stick with Summa Theologiæ.
- Although it is allowable to simply use “ae”, to make the “æ” character in MS Word use character code 00E6 under INSERT, or, to make it in HTML type “æ” where “ae” would have gone (e.g., “Summa Theologiæ”).
- **Aquinas never finished the Summa, but there is a Supplement compiled from his work on the Sentences attached to part three.
- Thomas’s “last name” derives from his family’s place of origin in Aquino, Italy – so, Thomas of Aquino. Thus, his name is rendered Thomas D’Aquino in Italian (Thomæ Aquinatis in Latin means “of Thomas Aquinas”). For an English source citation or bibliography entry, his name is typically listed as “Aquinas, Thomas.” (Thanks to Prof. R. Howe for this insight!)
- Full bibliographic information on the Summa should only be included in its firstand in the bibliography. After that, just use standard notation.Summa Theologica Citations
For more complete information see: https://douglasbeaumont.com/ and