Also known as Anandamayakosa - bliss/joy sheath

Buddhic Consciousness
The student will scarcely need to be told that all description of buddhic consciousness is necessarily and essentially defective. It is impossible in physical words to give more than the merest hint of what the higher consciousness is, for the physical brain is incapable of grasping the reality.
It is difficult enough to form a conception even of astral plane phenomena, there being four dimensions in the astral world. In the buddhic world there are no less than six, so that the difficulties are enormously enhanced.
There is an ingenious diagram (for which the [author] is indebted to the unknown designer) reproduced below, which illustrates graphically the fundamental difference between the buddhic plane and all the planes below it.
The diagram [Unity in Diversity] is seen to consist of a number of spikes or spokes which overlap at a certain point. That point of overlap is the beginning of the buddhic plane. The tips of the spokes represent the physical consciousness of men: they are separate and distinct from one another. Passing up the spokes towards the centre, we see that the astral consciousness is a little wider, so that the consciousness of separate men approach a little nearer to one another. The lower mental consciousnesses approach still more nearly to one another, whilst the higher mental consciousnesses, at their very highest level, meet at the point where the buddhic consciousness commences.


It will now be seen that the buddhic consciousness of each individual and separate "man," overlaps that of the other separate consciousnesses on either side of him. The illustration is the "overlapping" aspect of buddhic consciousness, where a sense of union with others is experienced.
As the consciousness rises still further up into the higher plane, it will be seen that it overlaps those on either side of it more and more, until eventually, when the "centre" is reached, there is practically a complete merging of consciousness. Nevertheless each separate spoke still exists and has its own individual direction and outlook. Looking out towards the lower worlds, each consciousness looks in a different direction: it is an aspect of the one central consciousness. Looking inwards, on the other hand, these diverging directions all meet together, and become one with one another.
The sense of union is characteristic of the buddhic plane. On this plane all limitations begin to fall away, and the consciousness of man expands until he realises, no longer in theory only, that the consciousness of his fellows is included within his own, and he feels and knows and experiences, with an absolute perfection of sympathy, all that is in them, because it is in reality a part of himself.
On this plane a man knows, not by mere intellectual appreciation, but by definite experience, the fact that humanity is a brotherhood, because of the spiritual unity which underlies it all, though he is still himself, and his consciousness is his own. ¹³


With the buddhic faculty it is no longer necessary to collect facts from outside, but one plunges into the consciousness of anything, whether it be mineral, plant or deva, etc., and understands it from inside. pg 318 Causal body ¹³
A selfish man could not function on the buddhic plane, for the very essence of that plane is sympathy and perfect comprehension, which excludes selfishness. There is a close connection between the astral and the buddhic bodies, the astral being in some ways a reflection of the buddhic. But it must therefore be supposed that a man can leap from the astral consciousness to the buddhic, without developing the intervening vehicles. The sense of personal property in qualities and in ideas is entirely lost, because we see that these things are truly common to all, because they are part of the great reality which lies equally behind all. Hence personal pride in individual development becomes an utter impossibility, for we now see that personal development is but as the growth of one leaf, among the thousands of leaves on one tree, and the important fact is not the size or shape of that particular leaf, but its relation to the tree as a whole; for it is only of the tree as a whole that we can really predicate permanent growth. We have ceased altogether to blame others for their differences from ourselves: instead we simply note them as other manifestations of our own activity, for now we see reasons which before were hidden from us. Even the evil man is seen to be part of ourselves - a weak part; so our desire is not to blame him, but to help him by pouring strength into that weak part of ourselves, so that the whole body of humanity may be vigorous and healthy. Thus when a man rises to the buddhic plane, he can gain the experience of others; hence it is not necessary for every Ego to go through every experience, as a separate individual. If he did not want to feel the suffering of another, he could withdraw: but he would choose to feel it, because he wants to help. He enfolds in his own consciousness one who is suffering, and although the sufferer would know nothing of such enfoldment, yet it will, to a certain extent, lessen his sufferings. On the buddhic plane there is a quite new faculty, having nothing in common with faculties on the lower planes. For a man recognises objects by an entirely different method, in which external vibrations play no part. The object becomes part of himself, and he studies it from the inside instead of the outside. With such a method of apprehension, it is clear that many familiar objects become entirely unrecognisable. Even astral sight enables one to see objects from all sides at once, as well as from above and below: adding to that the further complication that the whole inside of the body is laid out before us, as though every particle were placed separately upon a table: adding to that again the fact that, while we look at these particles, we are yet at the same time within each particle, and are looking through it, it is apparent that it becomes impossible to trace any resemblance to the object which we knew in the physical world. Whilst the intuition of the Causal Body recognises the outer, the intuition of buddhi recognises the inner. Intellectual intuition enables one to realise a thing outside oneself: with buddhic intuition one sees a thing from inside. Thus if, when working in the causal body, we want to understand another person, in order to help him, we turn our consciousness upon his causal body, and study its peculiarities; they are quite well marked, plainly to be seen, but they are always seen from without. If, wanting the same knowledge, we raise our consciousness to the buddhic level, we find the consciousness of the other man as part of ourselves. We find a point of consciousness which represents him - we might call it a hole rather than a point. We can pour ourselves down that hole, and enter into his consciousness, at any lower level that we wish, and therefore can see everything precisely as he sees it - from inside him instead of from outside. It will easily be understood how much that lends itself to perfect understanding and sympathy.
If, here and now, a hundred of us could simultaneously raise our consciousness into the buddhic world, we should all be one consciousness, but to each man that consciousness would seem to be his own, absolutely unchanged, except that now it included all the others as well. ¹³

A students experience of Buddhic consciousness

…....he described a sensation of actually rising through space; he found what he supposed to be the sky like a roof barring his way, but the force of his will seemed to form a sort of cone in it, which became a tube through which he found himself rushing. He emerged into a region of blinding light which was at the same time a sea of bliss so overwhelming that he could find no words to describe it. It was not in the least like anything that he had ever felt before; it grasped him as definitely and instantaneously as a giant hand might have done, and permeated his whole nature in a moment like a flood of electricity. It was more real than any physical object he had ever seen, and yet at the same time so utterly spiritual. “It was as though God had taken me into Himself and I felt His life running through me”. ¹⁹