The physicist cannot simply surrender to the philosopher the critical contemplation of the theoretical foundations for he himself knows best and feels most surely where the shoe pinches.... he must try to make clear in his own mind just how far the concepts which he uses are justified... The whole of science is nothing more than a refinement of everyday thinking.
We shall not flag or fail. We shall go on to the end. We shall fight in France, we shall fight on the seas and the oceans, we shall fight with growing confidence and growing strength in the air, we shall defend our island, whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills we shall never surrender.