of
impressions or thoughts, the latter through impressions or thoughts
recalling like ones in previous experience. When the same occurrence
affects different senses simultaneously, or nearly so, the association
is one of _contiguity_, as thunder and lightning, for a sound cannot be
_like_ a sight; when the same sense is affected in such a manner as to
recall a previous impression, the association is one of _similarity_, as
when the red autumn leaves recall the hue of sunset. Nearness in time or
nearness in kind is the condition of association.

The intensity or permanence of the association depends somewhat on
temperament, but chiefly on repetition or continuance. Not having an ear
for music, I may find it difficult to recall a song from hearing its
tune; but by dint of frequent repetition I learn to associate them.
Light and heat, smoke and fire, poverty and hunger so frequently occur
together, that the one is apt to recall the other. So do a large number
of antithetical associations, as light and darkness, heat and cold, by
_inverse similarity_, opposite impressions reviving each other, in
accordance with the positive and privative elements of a notion.

This brief reference to the laws of applied thought,--too brief, did I
not take for granted that they are generally familiar--furnishes the
clue to guide us through the labyrinth of symbolism, to wit, the
repeated association of the event or power recorded in the myth with
some sensuous image. Where there is a connection in kind between the
symbol and that for which it stands, there is _related_ symbolism; where
the connection is one of juxtaposition in time, there is _coincident_
symbolism. Mother Earth, fertile and fecund, was a popular deity in many
nations, and especially among the Egyptians, who worshipped her under
the symbol of a cow; this is related symbolism; the historical event of
the execution of Christ occurred by crucifixion, one of several methods
common in that age, and since then the cross has been the symbol of
Christianity; this is coincident symbolism. It is easy for the two to
merge, as when the cross was identified with a somewhat similar and much
older symbol, one of the class I have called "related," signifying the
reproductive principle, and became the "tree of life." As a coincident
symbol is to a certain extent accidental in origin, related symbols
have always been most agreeable to the religious sentiment.

This remark embodies the expla