Real Time, then, is a living reality, not discrete, not spatial in character--an utter contrast to that fictitious Time with which so many thinkers have busied themselves, setting up "as concrete reality the distinct moments of a Time which they have reduced to powder, while the unity which enables us to call the grains 'powder' they hold to be much more artificial. Others place themselves in the eternal. But as their eternity remains, notwithstanding, abstract since it is empty, being the eternity of a concept which by hypothesis excludes from itself the opposing concept, one does not see how this eternity would permit of an indefinite number of moments co-existing in it, an eternity of death, since it is nothing else than the movement emptied of the mobility which made its life." [Footnote: An Introduction to Metaphysics, pp. 51-54.] The true view of Time, as la duree, would make us see it as a duration which expands, contracts, and intensifies itself more and more; at the limit would be eternity, no longer conceptual eternity, which is an eternity of death, but an eternity of life and change--a living, and therefore still moving, eternity in which our own particular duree would be included as the vibrations are in light, [Footnote: Speaking in Matter and Memory on the Tension of la duree, Bergson calls attention to the "trillions of vibrations" which give rise to our sensation of red light, p. 272 (Fr. p. 229) Cf. La Conscience et la Vie in L'Energie spirituelle, p. 16.] an eternity which would be the concentration of all duree. Altering the old classical phrase sub specie aeternitatis, to suit his special view of Time, Bergson urges us to strive to perceive all things sub specie durationis. [Footnote: La Perception du Changement, p. 36.] Finally, Bergson reminds us that if our existence were composed of separate states, with an impassive Ego to unite them, for us there would be no duration, for an Ego which does not change, does not endure. La duree, however, is the foundation of our being and is, as we feel, the very substance of the world in which we live. Associating his view of Real Time with the reality of change, he points out that nothing is more resistant or more substantial than la duree, for our duree is not merely one instant replacing another--if it were there would never be anything but the present, no prolonging of the past into the actual, no growth of personality, and no evolution of the universe. La duree is the continuous progress of the past which gnaws into the future and which swells as it advances, leaving on all things its bite, or the mark of its tooth. This being so, consciousness cannot go through the same state twice; history does never really repeat itself. Our personality is being built up each instant with its accumulated experience; it shoots, grows, and ripens without ceasing. We are reminded of George Eliot's lines: