to subserve. It will be understood, therefore, why I have
spoken of applying a somewhat similar method, and not a precisely
similar method; to the problem of the pyramids. For whereas in dealing
with the origin of the week, I could from the very beginning of the
inquiry apply the _a priori_ method, I cannot do so in the case of the
pyramids. I do not know of any line of _a priori_ reasoning by which it
could be proved, or even rendered probable, that any race of men, of
whatever proclivities or avocations, would naturally be led to construct
buildings resembling the pyramids. If it could be, of course that line
of reasoning would at the same time indicate what purposes such
buildings were intended to subserve. Failing evidence of this kind, we
must follow at first the _a posteriori_ method; and this method, while
it is clear enough as to the construction of pyramids, for there are the
pyramids themselves to speak unmistakably on this point, is not
altogether so clear as to any one of the purposes for which the pyramids
were built.

Yet I think that if there is one purpose among possibly many which the
builders of the pyramids had in their thoughts, which can be
unmistakably inferred from the pyramids themselves, independently of all
traditions, it is the purpose of constructing edifices which should
enable men to observe the heavenly bodies in some way not otherwise
obtainable. If the orienting of the faces of the pyramids had been
effected in some such way as the orienting of most of our cathedrals and
churches--_i.e._, in a manner quite sufficiently exact as tested by
ordinary observation, but not capable of bearing astronomical tests,--it
might reasonably enough be inferred that having to erect square
buildings for any purpose whatever, men were likely enough to set them
four-square to the cardinal points, and that, therefore, no stress
whatever can be laid on this feature of the pyramids' construction. But
when we find that the orienting of the pyramids has been effected with
extreme care, that in the case of the great pyramid, which is the
typical edifice of this kind, the orienting bears well the closest
astronomical scrutiny, we cannot doubt that this feature indicates an
astronomical purpose as surely as it indicates the use of astronomical
methods.

But while we thus start with what is to some degree an assumption, with
what at any rate is not based on _a priori_ considerations, yet
manifestly we may expect