Authors:

The fact of the existence of two theories [causal and acausal] that contradict each other in Jung ... corresponds psychologically to the vascillation between 3 and 4.

Letter To Carl Alfred Meier, 1950.
The fact of the existence of two theories [causal and acausal] that contradict each other in Jung ... corresponds psychologically to the vascillation between 3 and 4.