You probably have read The Screwtape Letters and might remember that, in the 8th letter, Screwtape discusses the Law of Undulation. After some time thinking about it, I do not remember having heard about it or anything similar from any theologian (probably due to my scarce experience reading theology); nevertheless, this ‘law’ strikes me as something real, something which I recognize in my spiritual life. I would very much appreciate if you could tell me anything you know about it regarding theology. Maybe I can accept this law without it having theological background. Thank you for your time.
The law of undulation is, as far as I know, a term coined by Lewis. But it certainly describes lived human reality and is compatible with the teaching of the Church. I have found it very useful in grasping aspects of my own spiritual journey and how to offer each phase of it to God. And since it contains nothing contrary to faith, I have see no particular reason why you can’t incorporate it into your thinking. Beyond that, not much to add.