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Summa Theologiae · I, q. 3

Question 3. On the Simplicity of God

Thomas Aquinas, Summa Theologiae, First Part. 8 articles.

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Text: Summa Theologiae, Project Gutenberg #17611, First Part (Prima Pars), translated by the Fathers of the English Dominican Province. The First Part of the Summa in the English Dominican translation (first printed 1911 to 1925; second and revised edition from 1920). A sample check on 2026-11-09 against pre-1931 printings at the Internet Archive (first printings of 1915 and 1916 and the second and revised edition of the 1920s) found that the article text matches, with no 1947 introduction, synopsis, or index. The phrase “From the Complete American Edition” in Gutenberg's catalog title is a provenance note only. Question and article numbers were added by the transcriber. Rights: Public domain (US)

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When the existence of a thing has been ascertained there remains the further question of the manner of its existence, in order that we may know its essence. Now, because we cannot know what God is, but rather what He is not, we have no means for considering how God is, but rather how He is not.

Therefore, we must consider:

(1) How He is not;

(2) How He is known by us;

(3) How He is named.

Now it can be shown how God is not, by denying Him whatever is opposed to the idea of Him, viz. composition, motion, and the like. Therefore

(1) we must discuss His simplicity, whereby we deny composition in Him; and because whatever is simple in material things is imperfect and a part of something else, we shall discuss (2) His perfection; (3) His infinity; (4) His immutability; (5) His unity.

Concerning His simplicity, there are eight points of inquiry:

(1) Whether God is a body?

(2) Whether He is composed of matter and form?

(3) Whether in Him there is composition of quiddity, essence or nature, and subject?

(4) Whether He is composed of essence and existence?

(5) Whether He is composed of genus and difference?

(6) Whether He is composed of subject and accident?

(7) Whether He is in any way composite, or wholly simple?

(8) Whether He enters into composition with other things?

Articles

  1. Whether God Is a Body?
  2. Whether God Is Composed of Matter and Form?
  3. Whether God is the Same as His Essence or Nature?
  4. Whether Essence and Existence Are the Same in God?
  5. Whether God Is Contained in a Genus?
  6. Whether in God There Are Any Accidents?
  7. Whether God Is Altogether Simple?
  8. Whether God Enters into the Composition of Other Things?

Also online, linked only: the same translation at New Advent and the Latin text at Corpus Thomisticum. Neither is copied here.

Source: Thomas Aquinas. Summa Theologica, First Part. Project Gutenberg #17611. Project Gutenberg record. Public domain in the USA. Outside the U.S., check local copyright rules. Project Gutenberg notices retained. The full Project Gutenberg license is kept in the hosted text.