Beyond our ken
Beyond our understanding.
The word ken, meaning understanding or perception, is now rarely used outside Scotland. The first references to 'beyond our ken' aren't from the UK though but from America. The earliest I can find is in the Gettysburg newspaper The Republican Banner, in November 1834:
"But you in a strange mood to-day, and since the balloon is beyond our ken, you to dream of a flight through the air..."
That is in a rather fanciful story about a balloon trip and doesn't make the meaning clear. In 1864, William Whitney, in the proceedings of the Annual Reports Board of Regents of the Smithsonian Institute, made the meaning more explicit:
"The conditions of that ancient period, and the degree in which they could quicken the now sluggish processes of word-combination and formation are beyond our ken."
Much later, the term was taken up as the title of the popular BBC radio show 'Beyond Our Ken', starring Kenneth Horne, which ran from 1958 to 1964.