To attain this state, one simply continues to cultivate the fourth jhana and begins to not pay attention to the objects in the meditation space but gently to space itself. How big is reality? Tuning into the panoramic quality of attention itself when in the fourth jhana can be very helpful. This is quite a fine line, but it can definitely be done. Forms then slip away like ghosts into thin air, and the mind turns to boundless space, the fifth jhana, as the object of concentration.

This jhana is often called “Infinite Space”, as the next one is often called “Infinite Consciousness”, but I prefer the word “boundless” because it is much closer to the actual experience of these stages. People imagine that they might simultaneously perceive the whole of space, but what actually happens is that the perceptual boundaries drop away and a very unitive openness prevails. This open quality itself becomes the primary focus rather than what is unified in that openness. This aspect was already present in the fourth jhana, but now it comes to the fore. The same is true of the next formless realm.

This is not necessarily as perfectly clean as it sounds, depending on how solidly one is in this state, but it is still quite spectacular. When this state is really cultivated, all or most images and sense of a body are gone, and almost all that is left is vastness. There is still thought and the illusion of a separate self, i.e. duality, but the mind is extremely quiet and the duality subtle. The equanimity from the fourth jhana remains, as the formless realms use this state as their foundation. Sounds might still be noticeable depending on the depth of the state. Note, if one attains this state while meditating with the eyes open it may have a very different quality to it than if the eyes are closed.

From this state, the meditator has a few options. They can get stuck, which may be more likely if they are incorrectly practicing non-dual formless practices such as dzogchen by fixating too much on the phrase “space-like awareness.” They can also either go on to the next formless realm (boundless consciousness) or investigate this state and thus begin the progress of insight. If this last option is chosen, special care and extreme precision must be given to each and every instant that the many sensations that make up the perception of space, silence or equanimity are perceived so as to see each of these experiences arise and pass completely in each instant, not satisfy, and not be self.

It may seem odd to think of the sensations of space arising and passing away each instant, but space is a conditioned aspect of relative reality, and is thus impermanent like all other aspects of experiential reality. This can be an important attainment, as it clarifies that awareness, that non-thing that is often described as space-like, is actually not even space, though it is not separate from space, as in the chapter “No-self vs. True Self”.

There are few things quite as odd, profound, and possibly disconcerting as investigating the first three formless realms and perceiving them strobe in and out of existence, but this is powerful practice and a very valuable and high attainment. Again, this state may be left and insight practices begun with the benefits of the residue of this state calming, opening and stabilizing the mind for a short time after it ends.

MCTB Boundless Consciousness, The Sixth Jhana