A more or less superficial layer of the unconscious is undoubtedly personal. I call it the personal unconscious:
But this personal unconscious rests upon a deeper layer, which does not derive from personal experience and is not a personal acquisition but is inborn.
This deeper layer I call the collective unconscious. I have chosen the term “collective” because this part of the unconscious is not individual but universal; in contrast to the personal psyche, it has contents and modes of behaviour that are more or less the same everywhere and in all individuals. It is, in other words, identical in all men and thus constitutes a common psychic substrate of a suprapersonal nature which is present in every one of us.
Collected Works 9.1 ¶ 3
The collective unconscious is a part of the psyche which can be negatively distinguished from a personal unconscious by the fact that it does not, like the latter, owe its existence to personal experience and consequently is not a personal acquisition. While the personal unconscious is made up essentially of contents which have at one time been conscious but which have disappeared from consciousness through having been forgotten or repressed, the contents of the collective unconscious have never been in consciousness, and therefore have never been individually acquired, but owe their existence exclusively to heredity.
Collected Works 9.1 ¶ 88
Hence “at bottom” the psyche is simply “world.” In this sense I hold Kerényi to be absolutely right when he says that in the symbol the world itself is speaking. The more archaic and “deeper,” that is the more psychological, the symbol is, the more collective and universal, the more “material” it is.
Collected Works 9.1 ¶ 291