Despite all attempts at denial and obfuscation there is an unconscious factor, a black sun, which is responsible for the surprisingly common phenomenon of masculine split-mindedness, when the right hand mustn’t know what the left is doing. This split in the masculine psyche and the regular darkening of the moon in woman together explain the remarkable fact that the woman is accused of all the darkness in a man, while he himself basks in the thought that he is a veritable fount of vitality and illumination for the females in his environment. Actually he would be better advised to shroud the brilliance of his mind in the profoundest doubt. It is not difficult for this type of mind (which besides other things is a great trickster like Mercurius) to admit a host of sins in the most convincing way, and even to combine it with a spurious feeling of ethical surperiority without in the least approximating to a genuine insight. This can never be achieved without the participation of feeling; but the intellect admits feeling only when it is convenient. The novilunium of woman is a source of countless disappointments for man which easily turns to bitterness, though they could equally well be a source of wisdom if they were understood. Naturally this is possible only if he is prepared to acknowledge his black sun, that is, his Shadow.
– C. G. Jung, Mysterium Coniunctionis