presentation in individual dreams, and often when it displays two
elements close together in the dream content it warrants some special
inner connection between what they represent in the dream thoughts. It
should be, moreover, observed that all the dreams of one night prove on
analysis to originate from the same sphere of thought.

The causal connection between two ideas is either left without
presentation, or replaced by two different long portions of dreams one
after the other. This presentation is frequently a reversed one, the
beginning of the dream being the deduction, and its end the hypothesis.
The direct _transformation_ of one thing into another in the dream seems
to serve the relationship of _cause_ and _effect_.

The dream never utters the _alternative "either-or,"_ but accepts both
as having equal rights in the same connection. When "either-or" is used
in the reproduction of dreams, it is, as I have already mentioned, to be
replaced by "_and_."

Conceptions which stand in opposition to one another are preferably
expressed in dreams by the same element.[2] There seems no "not" in
dreams. Opposition between two ideas, the relation of conversion, is
represented in dreams in a very remarkable way. It is expressed by the
reversal of another part of the dream content just as if by way of
appendix. We shall later on deal with another form of expressing
disagreement. The common dream sensation of _movement checked_ serves
the purpose of representing disagreement of impulses--a _conflict of the
will_.

Only one of the logical relationships--that of _similarity, identity,
agreement_--is found highly developed in the mechanism of dream