The Summa Contra Gentiles is one of the best known works of Thomas Aquinas. His title was Liber de veritate catholicae fidei contra errores infidelium, which translates "Book on the truth of the Catholic faith against the errors of the unbelievers." The designation Summa Contra Gentiles was given to the work by later students and scribes. As this title is also Latin some explanation is in order. The word summa refers to what was a literary style of the day and the meaning is something like "to sum it all up." The work sums up the arguments against (contra) the gentiles, that is, unbelievers. (Our word gentile comes from this Latin word which is used to translate the Hebrew goy or nation.) It is generally thought that it was written around 1259–1265. Some think that it was a side project that was never actually completed. Wikipedia suggests that it was  "... to aid missionaries in explaining the Christian religion to and defending it against dissenting points of doctrine in Islam and Judaism." This seems to be the majority position.

Aquinas was part of a movement that we now call Scholasticism, sometimes described as the Theology of the Schools as contrasted with the Theology of the Monastics.  The Monastics were generally critical of this movement because of its "lack of discipline," the Scholastics replaced tradition and dogma with reason. Prior to 1100 or so Cathedral Schools and Monastic Schools (attached to monasteries) had dominated formal education. These schools were formed as the Roman Empire declined and the Church, which needed educated clergy, began to take its place in many spheres. Topics studied included the seven liberal arts: grammar, astronomy, rhetoric (persuasion), logic, arithmetic, geometry and music. Our modern Universities emerged from these and in Aquinas' day that was beginning to happen. Indeed Aquinas was educated at the studium generale (university) established by the Holy Roman Emperor Frederick II. (The universal language, or at least the language of the educated was Latin.) Scholastism is thought by many to be the beginning of rationalism. (Scholastisism emphasized critical thought and dominated the teaching by the scholastics, or school men.) While that may fit on some historical time line the point many try to make is that formal education has always been secular. That is certainly an overstatement and especially true when considering Aquinas. Aquinas believes that many "truths of God" are knowable through reason. There are some truths that cannot be known that way so revelation in necessary. That said, it is not a good reason to discount revelation.

If this is an apologetic text we observe that the apologist often has to step out of his own tradition in order to engage the gentiles on their own turf. A quick glance at the table below shows that Aquinas is arguing that faith and reason are not mutually exclusive additionally he offers proofs for the existence of God.

The form of the work is like an idealized classroom discussion. Questions (or propositions) are raised and solutions sought. We see propositions proposed and refuted in subsequent chapters.

The complete work can be found here. It is typically divided into four books as below, there are more chapters than are shown in my Highlights column but this gives the flavor of a book that requires much more study. Indeed it is widely read today.

Book  Title  Highlights
1 God
  • Chapter 1: The function of the wise man
  • Chapter 2: The author's purpose
  • Chapter 3: The truths we confess concerning God fall into two categories
  • Chapter 4: It is an advantage for the truths about God that are knowable by natural reason to be proposed to men to be believed on faith
  • Chapter 5: It is an advantage for things that cannot be discovered by reason to be proposed as tenets of the faith
  • Chapter 6: It is not foolish to assent to the truths of the Faith, even though they are beyond reason
  • Chapter 7: The truth of reason is not contrary to the truth of Christian Faith
  • Chapter 8: The relation of human reason to the truth of Faith
  • Chapter 9: The order and mode of proceding in this work
  • Chapter 10: The opinion of those who say that the existence of God, being self-evident, cannot be demonstrated
  • Chapter 11: Refutation of the above-mentioned opinion and a solution of the arguments
  • Chapter 12: The opinion of those who say that the existence of God cannot be demonstrated but is held by faith alone
  • Chapter 13: Arguments in proof of the existence of God
2 Creation
  • Chapter 1: The connection between the following considerations and the preceding ones
  • Chapter 2: That the consideration of creatures is useful for instruction of faith
  • Chapter 3: That knowledge of the nature of creatures serves to destroy errors concerning God
  • Chapter 4: That the philosopher and the theologian consider creatures in different ways
3 Part I Providence Q. 1-83
  • Chapter 5:  Arguments which seem to prove that evil is not apart from intention
  • Chapter 6: Answers to these arguments
  • Chapter 7: That evil is not an essence
  • Chapter 8: Arguments which seem to prove that evil is a nature or some real thing
  • Chapter 9: Answers to these arguments
3 Part II Providence Q. 84-163 An excerpt from this book follows



This excerpt below was part of the course material for the Theology 101 on line course from Hillsdale College. The lecture title was "Thomas Aquinas on Nature, Grace and Life in God." That is the focus of the section. That God helps in matters of faith and living is a major distinction between Christianity and other religions.

For most of the Jews I have known God is distant. Worship in Hebrew in the synagogue transports them to the otherworldliness where God is but they generally do not consider that He is or would walk with them daily and through all aspects of their lives. This also seems to be true for Muslims. The Muslims in my family are largely secular so that is not a good sample. The point of Hillsdale's course is that the God of the western tradition is a God who serves His creation and is available to his creation if we allow him in.