A distinction has been made between acuteness and subtlety of understanding. This might be illustrated by saying that acuteness consists in taking up the points or solid atoms, subtlety in feeling the air of truth.
William HazlittWe never do anything well till we cease to think about the manner of doing it. This is the reason why it is so difficult for any but natives to speak a language correctly or idiomatically.
William Hazlitt