Campbell addressed the issue many times in different ways: in his essay The Symbol without Meaning he writes:
.. a symbol, like everything else, shows a double aspect. We must distinguish, therefore between the 'sense' and the 'meaning' of the symbol. It seems to me perfectly clear that all the great and little symbolical systems of the past functioned simultaneously on three levels: the corporeal of waking consciousness, the spiritual of dream, and the ineffable of the absolutely unknowable. The term 'meaning' can refer only to the first two but these, today, are in the charge of science – which is the province as we have said, not of symbols but of signs. The ineffable, the absolutely unknowable, can be only sensed. It is the province of art which is not 'expression' merely, or even primarily, but a quest for, and formulation of, experience evoking, energy-waking images: yielding what Sir Herbert Read has aptly termed a 'sensuous apprehension of being
Try these youtube links and see if they will play on your internet connection. The second one is a full lecture on Joseph Campbell's: "The Symbol Without Meaning" taken from his book: "The Wild Gander". The above quote Tonyd used I believe is taken directly from that piece. John Lobell is a founding board member of the JCF and really knows this material well. He has a new book out by the way that is featured in the latest JCF MythBlast newsletter.
The link I sent you is good and was a short clip by Joseph covering the same concept. I think the problem has to do with certain youtube internet player concerns because this has come up before when I have tried to send one of these JCF channel clips. (However); you may be able to access them directly through you own connection by going direct to the Wisdom forum link and scrolling down to the link I provided that way. This link to the JCF video youtube channel has hundreds of short clips; (yes that's right - hundreds); taken from Joseph's lectures that have been collected by the staff volunteers targeting specific concepts that feature Joseph Campbell giving the talks and are not to be missed. For me they have been invaluable in understanding much of his material that has up till now been inaccessible. (Just keep clicking the reload button at the bottom of the page for more clips to be loaded.) Since Google owns YouTube your internet provider perhaps might have something to do with whether this will help you to access this site. I use both Yahoo and Google through Internet Explorer here in the US. If all else fails try typing #JosephCampbell in the YouTube search bar; and then click on the videos tab. ( This is how I found it. ) Other than that I'm not sure what else will work. Maybe technical support might be able to help.
The link to the forum page is below; then click the first entry link I provided and you should be able to search the various clips from there:
(The link for the John Lobell lecture is here.):
This is as close as I can get to breaking all this down. I hope it helps.