Further: if no philosophy as such is any longer required, then also there is no more need of any system, not even of any natural system of philosophy. The perception that all the processes of nature are systematically connected drives science on to prove this systematic connection throughout, both in general and in particular. But an adequate, exhaustive scientific exposition of this interconnection, the formation of an exact mental image of the world system in which we live, is impossible for us, and will always remain impossible. If at any time in the development of mankind such a final, conclusive system of the interconnections within the world – physical as well as mental and historical – were brought about, this would mean that human knowledge had reached its limit, and, from the moment when society had been brought into accord with that system, further historical development would be cut short – which would be an absurd idea, sheer nonsense. Mankind therefore finds itself faced with a contradiction: on the one hand, it has to gain an exhaustive knowledge of the world system in all its interrelations; and on the other hand, because of the nature both of men and of the world system, this task can never be completely fulfilled. But this contradiction lies not only in the nature of the two factors – the world, and man – it is also the main lever of all intellectual advance, and finds its solution continuously, day by day, in the endless progressive development of humanity, just as for example mathematical problems find their solution in an infinite series or continued fractions. Each mental image of the world system is and remains in actual fact limited, objectively by the historical conditions and subjectively by the physical and mental constitution of its originator.

1877: Anti-Duhring, Engels, p28