Without genetic knowledge, these would be insoluble mysteries.

But also one of great and insoluble mystery.

A similar point was made by the seventeenth-century philosopher John Locke, who saw it as an insoluble mystery.

I could merely agree with all Paris in considering them an insoluble mystery.

"My dear chap," I cried, "you shall always remain for them an insoluble mystery."

I will now consider the matter an insoluble mystery and dismiss it from my mind.

What his companions did not know was no insoluble mystery to him.

My mother could pull off a turkey, but stuffing remained an arcane, insoluble mystery.

Why these same saddle-back hills were not occupied by our own people is, it must be confessed, an insoluble mystery.

They were called criminals, and the outraged law, like the bursting shells, had come to them, an insoluble mystery from the sea.