Edited Extracts from http://www.studiesincomparativereligion.com/Public/articles/The_Heart_and_the_Cave-by_Rene_Guenon.aspx
and from http://www.studiesincomparativereligion.com/Public/articles/The_Mountain_and_the_Cave-by_Rene_Guenon.aspx
I am putting it here because I find the interpretation of the symbolism interesting. (Explanatory notes in parenthesis are mine.)
The close relationship between the symbolisms of the cave and the heart explains the function of the cave from the initiatic point of view as representing a spiritual center.
This “cave of the heart” is the vital center in which resides not only (Individual Soul) jīvātmā, but also unconditioned (Cosmic Self) Atmā which is in reality identical with (Ultimate Truth) Brahma itself,
The figure of the heart is a downward-pointing triangle (the “triangle of the heart” is yet another traditional expression); and this same figure also stands for the cave, whereas that of the mountain, or of the pyramid which is its equivalent, is on the contrary an upward-pointing triangle; this shows that we have here a relationship that is inverse, and also in a certain sense complementary.
According to the Hindu tradition, hidden in the “cave of the heart”:… is the principle of the being which, in this state of “envelopment” and with regard to manifestation, is compared with what is smallest, whereas it is in reality what is largest, just as the point is spatially infinitesimal and even null, although it is the principle by which all space is produced, or again, just as the number one appears as the smallest of numbers, although it contains them all principally and itself produces their whole unending series…..here then is the “beginning” of (spiritual) development, which is directly related to initiation in the etymological sense of this term; and it is precisely from this point of view that the cave can be considered as the place of the “second birth”.
“Know that this Agni, who is the foundation of the eternal world, and through whom that world may be attained, is hidden in the cave of the heart..”
It has already been mentioned that what resides in the heart is both jīvātmā, from the standpoint of individual manifestation, and unconditioned Atmā, from the principial point of view; the distinction between individual and principle is no more than an illusory one; it only exists with regard to manifestation, but in absolute reality they are one. These are “the two who have entered the cave”, and who, at the same time, are also said to “dwell on the highest summit”, so that the two symbolisms of the mountain and the cave are here united.
(Bolded Quotes are from Katha Upanishad)
The text adds that “those who know Brahma call them darkness and light”; (related to nara-narayana, the relationship between Arjuna and Krishna, the seeker and the truth)… the name Krishna denotes darkness of color and the name Arjuna denotes lightness of color,……they are considered as representing the un-manifested and the manifested.
A symbolism exactly akin in this respect is that of the Dioscorides in their correspondence with the two hemispheres, one dark and the other light..
On the other hand, these “two”, … are also the “two birds” who are mentioned in other texts as “dwelling on one and the same tree” .., and who are said to be “inseparably united” because they are really one, the distinction between them being no more than illusory,
….. it must be noted here that the symbolism of the tree is essentially “axial” like that of the mountain…
WE have seen that there is a close relationship between the mountain and the cave, inasmuch as both are taken as symbols of the spiritual centers, as are also, for obvious reasons, all the “axial” or polar symbols, amongst which the mountain is in fact one of the most important. In this respect the cave must be considered as being beneath the mountain or inside it, so as to be also on the axis; and this reinforces the already existing link between these two symbols, each of which is, in a sense, the complement of the other. It must be mentioned, however, so that we can “place” them in their exact mutual relationship, that the mountain is more “primordial” in its significance than the cave: it is so in virtue of being outwardly visible, we might even say of being the most visible object from all sides, whereas the cave is, on the contrary, an essentially hidden and closed place. It can easily be deduced from this that the representation of the spiritual center by the mountain corresponds to the original period of earthly humanity, during which the truth was wholly accessible to all (whence the name Satya-Yuga, the summit of the mountain being thus Satya-Loka or the “place of truth”); but when, owing to the downward march of the cycle, this truth was no longer within the scope of more than a fairly restricted “élite” (which coincides with the beginning of initiation in its strictest sense) and had become hidden from the majority, the cave was a more fitting symbol of the spiritual center and therefore of the initiatic sanctuaries which are its images…
By such a change, the center could be said not to have forsaken the mountain but merely to have withdrawn from its summit to its interior; on the other hand, this same change is as it were a “reversal”, through which, as we have explained elsewhere, the celestial world, indicated by the elevation of the mountain above the surface of the earth, has become in a certain sense the “subterranean world” (although in reality it is not this higher or inner world which has changed but the conditions of the outer world and consequently the relationship between the two worlds); and this “reversal” is shown in the respective figures which represent the mountain and the cave, and which express at the same time their complementarism.
As has already been mentioned the first of these two figures which represents also the pyramid and the mound which are symbolically equivalent to the mountain, is an up-pointing triangle; the figure of the cave is, on the contrary, a down-pointing triangle, being thus the inverse of the other. This inverted triangle is also the figure of the heart, and of the cup which in symbolism is generally assimilated to the heart as we have shown especially in connection with the Holy Grail
Moreover these last symbols, and others like them, from a more general point of view, refer to the passive or feminine principle of universal manifestation, or to one of its aspects,whereas the symbols which are figured by the up-pointing triangle correspond to the active or masculine principle, which all goes to bear out the complementarism in question. On the other hand, if the two triangles are placed one beneath the other, which corresponds to the situation of the cave beneath the mountain, it will be noticed that the lower triangle can be considered as the reflection of the upper triangle…
(Also refer to Shiva Shakti Symbolism
United and found in Hridaya ..the Heart Space)
(Plus elsewhere..just mentioning that one.)