We speak of Lenin's theory of reflection because in applying the views of Marx and Engels to the changed circumstances of his day, he extended those views substantially. Reactionary philosophers had seized on new data on the real nature of the world, which had overturned the old beliefs, and, by twisting the discovery that all knowledge is relative at any given moment, they were trying once more to confine cognition to the realm of agnosticism and idealism. This prompted Lenin to defend and develop the Marxist theory of cognition. Lenin defined matter as a philosophical category denoting objective reality, which is given to man by his sensations. In his theory of reflection, Lenin traced the transition from ignorance to knowledge, from incomplete and inaccurate knowledge to a more adequate understanding, and showed that this was a dialectical process, thus solving the problem of truth, which is central to the theory of cognition.
Objective truth is arrived at gradually, dialectically.
Lenin's theory of reflection represented a great advance in philosophy . He considered that a man was a genuine philosophical materialist only if he accepted that cognition is the reflection of the objective world in the human consciousness. And that principle is equally valid today, for the bitter controversy between materialism and idealism remains a living issue.