s and speculations which are esteemed no mean parts of learning,
are rejected as useless. But, how great a prejudice soever against our
notions this may give to those who have already been deeply engaged, and
make large advances in studies of that nature, yet by others we hope it
will not be thought any just ground of dislike to the principles and
tenets herein laid down, that they abridge the labour of study, and make
human sciences far more clear, compendious and attainable than they were
before.

135. Having despatched what we intended to say concerning the knowledge
of IDEAS, the method we proposed leads us in the next place to treat of
SPIRITS--with regard to which, perhaps, human knowledge is not so
deficient as is vulgarly imagined. The great reason that is assigned for
our being thought ignorant of the nature of spirits is our not having an
idea of it. But, surely it ought not to be looked on as a defect in a
human understanding that it does not perceive the idea of spirit, if it
is manifestly impossible there should be any such idea. And this if I
mistake not has been demonstrated in section 27; to which I shall here
add that a spirit has been shown to be the only substance or support
wherein unthinking beings or ideas can exist; but that this substance
which supports or perceives ideas should itself be an idea or like an
idea is evidently absurd.

136. OBJECTION.--ANSWER.--It will perhaps be said that we want a sense
(as some have imagined) proper to know substances withal, which,
if we had, we might know our own soul as we do a triangle. To this
I answer, that, in case we had a new sense bestowed upon us, we
could only receive thereby some new sensations or ideas of sense.
But I believe nobody will say that what he means by the terms soul
and substance is only some particular sort of idea or sensation.
We may therefore infer that, all things duly considered, it is
not more reasonable to think our faculties defective, in that they do not
furnish us with an idea of spirit or active thinking substance, than it
would be if we should blame them for not being able to comprehend a round
square.

137. From the opinion that spirits are to be known after the manner of an
idea or sensation have risen many absurd and heterodox tenets, and much
scepticism about the nature of the soul. It is even probable that this
opinion may have produced a doubt in some whether they had any soul at
all distinct from their body since