Obviously, in dealing with human beings old enough to talk, words afford the best evidence of perception. A man’s verbal responses to perceptive situations do not change much after the first few years of life. If you see a kingfisher, and at the same moment your companion says “there’s a kingfisher”, that is pretty conclusive evidence that he saw it. But, as this case illustrates, our evidence that some one else has perceived something always depends upon our own perceptions. And our own perceptions are known to us in a different way from that in which the perceptions of others are known to us. This is one of the weak spots in the attempt at a philosophy from the objective standpoint. Such a philosophy really assumes knowledge as a going concern, and takes for granted the world which a man derives from his own perceptions. We cannot tackle all our philosophical problems by the objective method, but it is worth while to proceed with it as far as it will take us. This whole question of perception will have to be attacked afresh from a different angle, and we shall then find reason to regard the behaviouristic standpoint as inadequate, though valid so far as it goes. We have still, however, a long road to go before we shall be driven to consider the subjective standpoint; more particularly, we have to define “knowledge” and “inference” behaviouristically, and then, making a new start, to consider what modern physics makes of “matter”. But for the moment there are still some things to be said about perception from the objective standpoint.