I don't think any man feels well grounded in knowledge unless he has a good basis of mathematical certainties, and knows how to deal with them and apply them to every branch of knowledge where they can come in to advantage.
 Oliver Wendell Holmes Sr., The Poet at the Breakfast-Table (1872). copy citation

Context

“It seems as if every well-organized mind should be able to handle numbers and quantities through their symbols to an indefinite extent; and yet, I am puzzled by what seems to a clever boy with a turn for calculation as plain as counting his fingers. I don't think any man feels well grounded in knowledge unless he has a good basis of mathematical certainties, and knows how to deal with them and apply them to every branch of knowledge where they can come in to advantage. Our Young Astronomer is known for his mathematical ability, and I asked him what he thought was the difficulty in the minds that are weak in that particular direction, while they may be of remarkable force in other provinces of thought, as is notoriously the case with some men of great distinction in science.” source