A real woman does a great many things without knowing why she does them
 Oliver Wendell Holmes Sr., The Professor at the Breakfast-Table (1860). copy citation

Context

“Why, the one that came with our little beauty, the old fellah in petticoats. —Now that means something,—said I to myself.—These rough young rascals very often hit the nail on the head, if they do strike with their eyes shut. A real woman does a great many things without knowing why she does them; but these pattern machines mix up their intellects with everything they do, just like men. They can't help it, no doubt; but we can't help getting sick of them, either. Intellect is to a woman's nature what her watch-spring skirt is to her dress;” source