later time; for the later state did not supersede the previous state,
but only showed a more coherent form of it, which was generally true to
the original system but was more determinate. Evolution through history
has in Western countries often brought forth the development of more
coherent types of philosophic thought, but in India, though the types
remained the same, their development through history made them more and
more coherent and determinate. Most of the parts were probably existent
in the earlier stages, but they were in an undifferentiated state; through
the criticism and conflict of the different schools existing side by side
the parts of each of the systems of thought became more and more
differentiated, determinate, and coherent. In some cases this development
has been almost imperceptible, and in many cases the earlier forms have
been lost, or so inadequately expressed that nothing definite could be
made out of them. Wherever such a differentiation could be made
in the interests of philosophy, I have tried to do it. But I
have never considered it desirable that the philosophical interest
should be subordinated to the chronological. It is no

6

doubt true that more definite chronological information would be
a very desirable thing, yet I am of opinion that the little
chronological data we have give us a fair amount of help in forming
a general notion about the growth and development of the different
systems by mutual association and conflict. If the condition of the
development of philosophy in India had been the same as in Europe,
definite chronological knowledge would be considered much more
indispensable. For, when one system supersedes another, it is
indispensably necessary that we should know which preceded and which
succeeded. But when the systems are developing side by side, and when