Early in 1918 the "Académie française" received Bergson officially when he took his seat among "The Select Forty" as successor to Emile Ollivier (the author of the historical work "L'Empire libéral"). A session was held in January in his honour at which he delivered an address on Ollivier. In the war, Bergson saw the conflict of Mind and Matter, or rather of Life and Mechanism; and thus he shows us the central idea of his own philosophy in action. To no other philosopher has it fallen, during his lifetime, to have his philosophical principles so vividly and so terribly tested.[citation?]