It may happen, as with the electron, that a string of events are so interconnected causally that it is practically convenient to regard them as forming one entity, but where this happens it is a scientific fact, not a metaphysical necessity. The whole question of personal immortality, therefore lies outside philosophy, and it is to be decided, if at all, either by science or by revealed religion. I will take up another matter in regard to which what I have said may have been disappointing to some readers. It is sometimes thought that philosophy ought to aim at encouraging a good life. Now, of course, I admit that it should have this effect, but I do not admit that it should have this as a conscious purpose. To begin with, when we embark upon the study of philosophy we ought not to assume that we already know for certain what the good life is; philosophy may conceivably modify our views as to what is good, in which case it will seem to the non-philosophical to have had a bad moral effect. That, however, is a secondary point. The essential thing is that philosophy is part of the pursuit of knowledge, and that we cannot limit this pursuit by insisting that the knowledge obtained shall be such as we should have thought edifying before we obtained it. I think it could be maintained with truth that _all_ knowledge is edifying, provided we have a right conception of edification. When this appears to be not the case it is because we have moral standards based upon ignorance. It may happen by good fortune that a moral standard based upon ignorance is right, but if so knowledge will not destroy it; if knowledge can destroy it, it must be wrong. The conscious purpose of philosophy, therefore, ought to be solely to _understand_ the world as well as possible, not to establish this or that proposition which is thought morally desirable. Those who embark upon philosophy must be prepared to question all their preconceptions, ethical as well as scientific; if they have a determination never to surrender certain philosophic beliefs, they are not in the frame of mind in which philosophy can be profitably pursued.