esides our earth are included.
During sleep, therefore,--(this can be made clear, as we have said, only by
further explanations)--it enters a world to which other stars than the
earth belong. In recognition of the fact that man lives during sleep in a
world of stars, that is, in an astral world, occult science calls that
principle of man which has its real home in that "astral" world and which,
every time it returns to the sleep state, draws renewed force from that
world, the _astral body_.

It should be superfluous to point out that a misunderstanding might easily
arise with regard to these facts; in our time, however, when certain
materialistic modes of representation exist, it becomes quite necessary to
draw attention to them. In quarters where such representation prevails it
may, of course, be said that such a thing as fatigue can be scientifically
investigated only in accordance with physical conditions. Even if the
learned are not yet unanimous with regard to the physical cause of
fatigue, one thing is quite firmly established; we must accept certain
physical processes which lie at the root of this phenomenon. It would be
well, however, if it were recognized that occult science does not in any
way oppose this assertion. It admits everything that is said in this
connection, just as it is admitted that for the physical erection of a
house one brick must be laid upon another, and that when the house is
finished its form and construction can be explained by purely mechanical
laws. But the thought of the architect is necessary for the building of
the house. This cannot be discovered merely by examination of physical
laws.

Just as the thought of the creator of a house stands behind the physical
laws which make it explicable, so too, behind what is affirmed, with
perfect accuracy by physical science, stands that of which occult science
treats. This comparison is of course often put forward when the
justification for a spiritual background to the world is in question; and
it may be considered a trivial one. But what is important in such matters
is not familiarity with certain conceptions, but that the proper weight
should be given them in establishing a fact. One may be prevented from
doing this simply because contrary ideas have so much power over the
judgment that this weight is not felt.

Dreaming is an intermediate state between sleeping and waking. What dream
experiences offer to thoughtful observation is the many