This study attempts to demonstrate that there is a new turn in Collingwood's philosophy of history in and after 1935 and that this new turn is the result of Collingwood working out his theory of absolute presuppositions in the early 1930's. Collingwood's unpublished manuscripts are examined in order to assist us in justifying this claim. A clarification of the theory of absolute presuppositions follows our attempt to situate this theory in Collingwood's intellectual development. After arguing that absolute presuppositions are logico-regulative entities, we suggest that Collingwood is a foundationalist in a unique sense and that he can solve the problem of conceptual change in consistently rational terms. Although we argue against the view that there are radical discontinuities in his thought, we contend that Collingwood's principles of metaphysics, uncovered in the early 1930's, throw new light on his analysis of history in The Idea Of History. We argue that absolute presuppositions underlie all attempts at a theory of historical explanation. We attempt to show that absolute presuppositions logically regulate the historical imagination and that the historical imagination has changed over time as the result of absolute presuppositions changing. We argue that there is a logico-regulative relationship of absolute presuppositions to historical evidence over time. We also argue that it is necessary to account for Collingwood's acceptance of the incommensurate thesis in 1925 and his rejection of this thesis in 1936 for question-and-answer complexes. We claim that it was Collingwood's newly uncovered principles of metaphysics in the early 1930's that account for his about-face on the subject of rethinking question-and-answer complexes. Collingwood still accepted the incommensurate thesis for contexts of irrmediacy, and so his new position was not a radical change, but his principles of metaphysics did provide a ground or basis for the possibility of re-thinking an identical questionand- answer complex. / Thesis / Doctor of Philosophy (PhD)