David Hume (1711-1776) is regarded as the most important philosopher ever to have written in English, and the third in the triumvirate of the classical British empiricists which include Locke and Berkeley.

Hume's basic contribution was to distinguish forcefully observations and conceptions which are discoverable a priori by reason, such as geometrical proofs, and observations and conceptions which are matters of fact, such as power and causation, but which lack the "medium" of deductive inference. These latter our reason takes to be realities, but Hume insisted that we have no entitlement to know these realities. When it comes to matters of fact, we simply construct a reality, largely by means of the imagination, based on what people like us have done in the past and how we expect nature and convention to behave in the future.

For Hume, convention frames our entire notion of power or energy. In reality, we know as little about energy as we know about the interior of the sun, or the interior of the earth for that matter. The way in which anticipatory convention frames our observation and conception of energy and causation may excite "wonder and admiration," but to reach clear and distinct ideas about energy per se, we need to plumb a "secret connexion" in our consciousness between states that precede a change and those which follow upon it.

Goethean conversation gives us a way to open up the "secret connexion" between moods or states of consciousness that follow one from another under certain conditions, and to learn whether and how these connexions are fundamentally geometrical. A geometrical understanding of consciousness and conversation Hume would approve. The rest, including much of the imaginative freedom talk we witness in the day to day, he would condemn to the ash heap.