ly exercised without bias. In the following pages the
various conditions of the earth's evolution, as given by occult science,
will be detailed. The transformation of our planet will be traced down to
the conditions of life in which we now find it. Any one who surveys what
comes before him at the present time merely through the evidence of his
senses, and then lends an ear to what occult science has to say on the
subject, namely:--how that which now lies before him has been evolved from
a far distant past,--will be able, if his thought is genuinely unbiased, to
say to himself: "In the first place, what occult science reports is quite
logical; in the second place, I can, if I assume the reports of occult
investigation to be correct, understand how things have become as they now
appear." By "logical" is not meant, in this connection, of course, that
errors might not be made from a logical standpoint in some description
given by occult research. We are here speaking of "logic" as it is
understood in the ordinary life of the physical world. Just as a logical
demonstration is accepted there as it is in physical research, even though
a single investigator, in a certain domain of facts, may make illogical
statements, so is it also with regard to occult science. It may even
happen that an investigator who possesses the power of vision in
supersensible spheres may make mistakes in a logical presentment of them,
and may be corrected by another who has no supersensible perception, but
has, none the less, a capacity for sound thinking. In reality, nothing of
any weight can be said against the logical deductions of occult science.
And it ought to be unnecessary to insist that nothing can be adduced, on
purely logical grounds, against the facts themselves. In the domain of the
physical world it can never be proved by logic, but only by ocular
demonstration, whether or no there is such an animal as a whale;
similarly, supersensible facts can be known only through occult
perception.

But it cannot be sufficiently emphasized that an obligation is laid upon
the explorer of supersensible regions, before he determines to approach
the invisible worlds with his own power of perception, to acquire first of
all the aforementioned logical faculty, and this is none the less
essential if he recognizes that the world, manifest to his senses, will
become comprehensible if he accepts the communications of occult science
as correct. All experiences in