What is on first principles about?

Origen, answered from the texts and cited to the page.

Origen answers

On First Principles is an attempt to lay out the scientific knowledge of the ecclesial faith in a coherent and ordered way, so that a reader might be led from that foundation into the deeper mysteries of theology and cosmogony.1 The work is structured around two great cycles, which I call theology and economy.2 In the first cycle, I treat God, Christ, the Holy Spirit, and rational beings at the level of their nature — what they are, considered as directly as our feeble minds allow.

In the second cycle, I return to each of these same subjects and treat them at the level of their activity in history and in the salvation of creatures.3 The distinction matters: in the first cycle God is treated rather abstractly, focusing on his being bodiless; in the second, it is specified that this one God is the God of the Law and the Prophets and the Father of our Lord Jesus Christ.4

Within that structure I also maintain a further distinction, one that runs throughout the whole work: between what the apostles delivered with utmost clarity, which I call the apostolic preaching, and what they merely asserted while leaving the grounds of their statements open for further reflection, which I call the ecclesiastical preaching.5

Some matters I treat by dogmatic definition; others I treat, as I say plainly at the opening of the second part, more through discernment of inference than by dogmatic definition.6 The reader should not mistake the second kind of treatment for the first. Where the rule of faith has spoken, I follow it; where it has not, I offer possibilities for examination rather than conclusions to receive.

There is also a third part, on Scripture itself — its divine inspiration and how it must be read — followed by a recapitulation of the whole.7 This is not an afterthought. The entire work rests on the claim that Scripture carries a body, a soul, and a spirit, and the account of how to read it belongs at the end because only a reader who has followed the theological and economic argument is in a position to understand why the method is necessary.

Sources

  1. The work was intended to demonstrate the grounding of his hermeneutic in a coherently presented account of the scientific knowledge of the ecclesial faith, which in turn would lead his readers into the deeper mysteries of theology and cosmogony.
    On First Principles, pp. 55–56
  2. The most appropriate terms to describe the respective treatments in the two cycles are 'theology'... and 'economy.'
    On First Principles, p. 39
  3. In the first cycle, rational beings are discussed in terms of their arrangement; in the second, the focus is much more on the struggles in which they find themselves.
    On First Principles, p. 39
  4. In the first cycle God is treated rather abstractly, focusing primarily on his being bodiless; in the second cycle it is specified that this one God is the God of the Law and the Prophets and the Father of our Lord Jesus Christ.
    On First Principles, p. 39
  5. he does in fact make a distinction, between those things which the apostles 'delivered with utmost clarity' and those that they merely asserted, leaving the grounds of their statements for further reflection.
    On First Principles, p. 41
  6. The reference to having treated some matters 'more through discernment of inference than by dogmatic definition' only applies to the latter part of the preceding chapter.
    On First Principles, p. 41
  7. Part Three: The Inspired Scripture — That the Scriptures are Divinely Inspired (4.1) How One Must Read and Understand the Scriptures (4.2-3) Recapitulation (4.4)
    On First Principles, pp. 43–44