In any creative activity, our powers of invention stimulate the mind, in much the same way fertilizer in a vineyard helps the grapes grow to make wine. By engaging these powers, particularly insight and synthesization, our mental and creative capacity is nurtured and nourished.
Both the intellect and emotions help create novel ideas, images, forms, etc., but it is insight that leads us to the innermost nature of things.
Art could not exist apart from subjectivity. Subjective insight can reach or seize the value or aspects of things that objective insight cannot. Subjectivity mediates between the intellect and emotions to draw art or poetry from things both existent or nonexistent.