IN the annual philosophical lecture on “Some Problems of the Philosophy of History” delivered under the Henriette Hertz Trust before the British Academy on March 16 (London: Oxford University Press, Is. 6d. net), Prof. G. C. Field urged that all serious philosophical thinking must be based on an examination of the assumptions actually made in the other established forms of thinking. If the philosopher wishes to proceed eventually to a general theory of knowledge or reality, he must take this as his foundation and evidence. Prof. Field suggested that among the established forms of thinking, history holds an important place and deserves serious consideration in view of the tendency to suggest that the assumptions of physical science must be the assumptions of all valid thinking. History forms a coherent body of thought in which mutual understanding and cooperation between large numbers of people are possible, and has independent claims to consideration as an essential part of the evidence on which our final theories must be based. Prof. Field distinguishes three main elements in the general structure of historical thinking: imaginative reconstruction of past events or situations ; the belief that this imaginative reconstruction is correct, corresponding to, or being like in some degree, what really happened ; and the evidence on which our conclusions are based. Discussing the dependence of our historical beliefs on narrative, he referred to the question of selection in imaginative reconstruction and its bearing on the understanding rather than the mere recording of what happened.