From Chapter 18 of R. A. Lafferty's historical novel Okla Hannali:

There is an interesting question in the Summa of St. Thomas Aquinas and also in an old science fiction story, the name of which I forget, concerning the paradox of free will and predestined fate. It asks whether a man in making a great decision that will forever set the seal on his future does not also set the seal on his past. A man alters his future, and does he not also alter his past in conformity with it? Does he not settle not only what manner of man he will be, but also what manner of man he has been?

What is the passage in Summa that Lafferty alludes to, and how does it relate to what Lafferty is saying here?

I found a couple of mentions of "free will" in Summa Theologica but they didn't seem relevant to the quoted passage from Lafferty. But I'm not a philosopher or theologian, and probably didn't understand what I was reading.

I posted a related question to scifi.stackexchange.com asking for the identification of the science fiction story Lafferty mentions.

  • 2
    Why do you think it is Summa Theologica and not Summa Contra Gentiles that has an entire book on Providence, contingents and freedom of choice? Ch. 158 has something along those lines.
    – Conifold
    Commented Jan 28 at 5:57
  • Ignorance, sir, pure ignorance. I didn't even know that Aquinas had more than one Summa. Thank you.
    – user14111
    Commented Jan 28 at 6:33

1 Answer 1


Until recently, it was not seldom to encounter Jorge Borges's such witty inventions as the taxonomy of animals from "a certain Chinese Encyclopaedia" taken as veridical. I think, as I shall explain, the cited paragraph is Lafferty's own playful composition to some extent like Borges's, and notably, as rich in philosophical content as they are. Hence, a specification of the mentioned allusions will be inescapably a matter of guesswork.

While Thomas Aquinas intensively explored the concepts of human agent's free will as opposed to predestination and predetermination, albeit in a theological setting, the paragraph suggests quite modern metaphysical views (aye, philosophy advances in its own peculiar style) that we cannot expect to immediately find in his writings. The appropriate location to start making connections between the paragraph and Thomas Aquinas's views may be Question 23 in the first part of Summa Theologiae, in particular, the question “Whether the foreknowledge of merits is the cause of predestination?”

The complementary text, “an old science fiction story,” may be his own Thus We Frustrate Charlemagne (Galaxy, February 1967, pp. 126-136). The relevant feature of the plot is that an artificially intelligent machine and a group of people attempt to alternate the history by changing past events. Though the history really changes, they do not realise it, for they do not perceive any difference.

Just for the sake of illustration, such a crude construction might be offered: Suppose we have acted in a way at our discretion. By this act, we have chosen a particular predestined history, hence, a past (and future) chain of causes and effects (terminating at God’s initial creation of the soul). Through each act of ours, we get on with a predestined course of life. We do not get aware of the change in our history, in our past manner of being, we see a linear, single progression.

No doubt elaborate articulation of the paragraph could be conjured up merging with one's philosophical views and one's reflections on Thomas Aquinas's thought and Lafferty's story. Also, other choices could be made for the alluded question and fiction. Indeed, I believe that is Lafferty's point: to provoke reader's thought towards the misty ideas he has touched on.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .