Ah, but life is like that! It does not permit you to arrange and order it as you will. It will not permit you to escape emotion, to live by the intellect and by reason! You cannot say, 'I will feel so much and no more.' Life, Mr. Welman, whatever else it is, is not reasonable. [Hercule Poirot]
Intuition is like reading a word without having to spell it out. A child can't do that because it has had so little experience. A grown-up person knows the word because they've seen it often before.
Any medical man who predicts exactly when a patient will die, or exactly how long he will live, is bound to make a fool of himself. The human factor is always incalculable. The weak have often unexpected powers of resistance, the strong sometimes succumb.
Curious things, habits. People themselves never knew they had them. [Witness for the Prosecution, also published in The Hound of Death and Other Stories.]