TWO:My obligations to other writers have been acknowledged throughout this work, so far as I was conscious of them, and so far as they could be defined by reference to specific points. I take the present opportunity for mentioning in a more general way the valuable assistance which I have derived from Schweglers Geschichte der Griechischen Philosophie, Langes Geschichte des Materialismus, and Dührings Geschichte der Philosophie. The parallel between Socrates, Giordano Bruno, and Spinoza was probably suggested to mexxiv by Dühring, as also were some points in my characterisation of Aristotle. As my view of the position occupied by Lucretius with respect to religion and philosophy differs in many important points from that of Prof. Sellar, it is the more incumbent on me to state that, but for a perusal of Prof. Sellars eloquent and sympathetic chapters on the great Epicurean poet, my own estimate of his genius would certainly not have been written in its present form and would probably not have been written at all.
