To treat of intellectual egotism first, the danger that besets such people as I have described is a want of sympathy with other points of view, and the first thing that such natures must aim at, is the getting rid of what I will call the sectarian spirit.  We ought to realize that absolute truth is not the property of any creed or school or nation; the whole lesson of history is the lesson of the danger of affirmation.  The great difference between the modern and the ancient world is the growth of the scientific spirit, and the meaning and value of evidence.  There are many kinds of certainties.  There is the absolute scientific certainty of such propositions as that two and two make four, and cannot possibly make five.  This is of course only the principle that two and two cannot be said to make four, but that they are four, and that 2 + 2 and 4 are only different ways of describing the same phenomenon.  Then there come the lesser certainties, that is to say, the certainties that justify practical action.  A man who is aware that he has twenty thousand pounds in the hands of trustees, whose duty it is to pay him the interest, is justified in spending a certain income; but he cannot be said to know at any moment that the capital is there, because the trustees may have absconded with the money, and the man may not have been informed of the fact.  The danger of the egotist is that he is apt to regard as scientific certainties what are only relative certainties; and the first step towards the tolerant attitude is to get rid of these prejudices as far as possible, and to perceive that the first duty of the philosopher is not to deal in assumptions, but to realize that other people’s regions of what may be called practical certainties—­that is to say, the assurances which justify practical action—­may be both smaller or even larger than his own.  The first duty then of the man of vivid nature is to fight resolutely against the sin of impatience.  He must realize that some people may regard as a certainty what is to him a questionable opinion, and that his business is not the destruction of the certainties of others, but the defining the limits of his own.  The sympathy that can be practised intellectually is the resolute attempt to enter into the position of others.  The temptation to argue with people of convinced views should be resolutely resisted; argument only strengthens and fortifies the convictions of opponents, and I can honestly say that I have never yet met a man of strong intellectual fibre who was ever converted by argument.  Yet I am sure that it is a duty for all of us to aim at a just appreciation of various points of view, and that we ought to try to understand others rather than to persuade them.