manner is an important feature of Sanskrit thought, but from the ninth
century onwards, the habit of using clear, definite, and precise
expressions, began to develop in a very striking manner, and as a result
of that a large number of technical terms began to be invented. These
terms are seldom properly explained, and it is presupposed that the reader
who wants to read the works should have a knowledge of them. Any one in
olden times who took to the study of any system of philosophy, had to do
so with a teacher, who explained those terms to him. The teacher himself
had got it from his teacher, and he from his. There was no tendency to
popularize philosophy, for the idea then prevalent was that only the
chosen few who had otherwise shown their fitness, deserved to become
fit students (_adhikârî_) of philosophy, under the direction of a
teacher. Only those who had the grit and high moral strength to devote
their whole life to the true understanding of philosophy and the
rebuilding of life in accordance with the high truths of philosophy
were allowed to study it.

Another difficulty which a beginner will meet is this, that sometimes
the same technical terms are used in extremely different senses in
different systems. The student must know the meaning of each technical
term with reference to the system in which it occurs, and no dictionary
will enlighten him much about the matter [Footnote ref 1]. He will have
to pick them up as he advances and finds them used. Allusions to the
doctrines of other systems and their refutations during the discussions
of similar doctrines in any particular system of thought are often very
puzzling even to a well-equipped reader; for he cannot be expected to
know all the doctrines of other systems without going through them, and
so it often becomes difficult to follow the series of answers and
refutations which are poured forth in the course of these discussions.
There are two important compendiums in Sanskrit giving a summary of some