Bertrand Russell Quotes（バートランド・ラッセルの名言・警句)

　

Is there any knowledge in the world which is so certain that no reasonable man could doubt it? This question, which at first sight might not seem difficult, is really one of the most difficult that can be asked. When we have realized the obstacles in the way of a straightforward and confident answer, we shall be well launched on the study of philosophy.
　Source:The Problems of Philosophy, chap. 1 (1912)
　More info.:http://russell-j.com/R601.HTM