“A truth is not necessary, because we negatively are not able to conceive the actual existence of the opposite thereof;but a truth is necessary when we positively are able to apprehend that the negation thereof includes an inevitable contradiction. It is not that that we can see how the opposite comes to be true, but it is that the opposite can not possibly be true.”

“There are trivial truths and there are great truths. The opposite of a trivial truth is plainly false. The opposite of a great truth is also true.”

“You can recognize a small truth because its opposite is a falsehood. The opposite of a great truth is another truth.”

“The opposite of every truth is just as true.”

“The dream has a very striking way of dealing with the category of opposites and contradictions. This is simply disregarded. To the dream 'No' does not seem to exist. In particular, it prefers to draw opposites together into a unity or to represent them as one. Indeed, it also takes the liberty of representing some random element by its wished-for opposite, so that at first one cannot tell which of the possible poles is meant positively or negatively in the dream-thoughts.”

“Across planes of consciousness, we have to live with the paradox that opposite things can be simultaneously true.”