The meditator starts investigation from a superficial level at which gross, solidified truths appear. But as one observes the apparent truth objectively, one starts penetrating from gross to subtler truths and finally witnesses ultimate truth. This ultimate truth can be experienced only only by exploring reality within oneself.

The exploration of the truth within is Vipassana meditation. In the course of this exploration the meditator must investigate two fields, two aspects of reality: matter and mind. Investigation of the physical reality is called in Pāli kāyānupassanā. Investigation of the mental reality is called cittānupassanā. In fact, however, matter and mind cannot be experienced separately from each other because they are interdependent, interconnected.

Exploring one is bound to involve an exploration of the other. Neither can be fully understood without the other.

The field of matter: kāyānupassanā and vedanānupassanā

The physical reality of oneself must be invwestigated by direct experience; it will not help merely to imagine or speculate about it. How then to experience this truth, the reality of one’s own body? If in the names of kāyānupassanā one sits with closed eyesand simply names or imagines the different parts of the body, such a person is far away from correct practice of Vipassanā, from the direct exploration of truth. We actually experience our bodies by feeling them - that is, by means of our bodily sensations. Therefore awareness of physical sensation is indispensable to the practice of kāyānupassanā. Sensations exists, of one type or another, at every part, every atom of the body.

Thus the investigation of the truth of body is bound to involve the exploration of bodily sensations - in Pāli, vedanānupassanā. Sensations can be experienced only within one’s body, and the reality of body can be experienced only by means of sensations.

But though sensation is always based on the body, the truth of vedanā is not exclusively physical in nature; it is also one of the four mental aggregates. Sensation overlaps the two fields of mind and matter. For this reason observations of sensation, as we shall see, is a way to explore the mental-physical phenomenon in its entirety.

In the practice of kāyānupassanā, observation of sensations will enable the meditator to experience directly the changing nature of the physical structure. By examining every part of the body in turn, one realizes that all sensations arise and pass away. As one repeats this practice, eventually a stage comes in which one experiences the instantaneous dissolution of every particle of the body. In this very subtle stage the meditator observes directly that the entire material structure is dissolving every moment; this experience is called in Pāli bhaṇga-ñāṇa, the realization of the truth of dissolution.

Through observing sensations as well, one can experience that the body is composed of four basic elements: earth, or solidity; water, or fluidity; air, or gaseousness; and fire, or temperature. Particles arise with the predominance of one or more elements, giving rise to the infinite variety of sensations. They arise to pass away. Ultimately the body is merely wavelets arising and passing away, constant dissolving. The apparently solid material structure is in reality nothing but ripples, vibrations, oscillations.

This truth of anicca can be realized directly only by the experience of bodily sensations. With this realization comes the understanding that one has no control over the changes constantly occurring in the body - aniccā. Therefore any attachment to what is changing beyond one’s control is bound to bring nothing but suffering - dukkha. Knowing these facts now by personal experience, the meditator develops the wisdom of equanimity. By observing sensations he has reached the ultimate truth about body, and as a result his attachment to the body is shattered. He emerges from the folly of identifying with the body and develops real detachment, real enlightenment.

In the practice of vedanānupassanā as well, the meditator gives importance to observing all that happens within the body, all sensations. Whether they are pleasant, unpleasant, or neutral one learns to observe them objectively, and by doing so one breaks the old habit of wallowing in sensory experiences. By repeatedly observing the arising and passing away of sensations, the meditator learns not to be swayed by them, to keep an inner balance in the face of any experience whatsoever.

In this way the sensations that arise within the body are the base for the practice of both kāyānupassanā and vedanānupassanā. By investigating sensations the meditator explores to the depths the reality of the physical atructure. The understanding arises, "Such is the body and such are bodily sensations, which create so many illusions and complications for us!" Previously one may have understood these phenomena intellectually, but now this understanding becomes the wisdom that develops from experience - the experience of bodily sensations.

The field of mind: cittāmupassanā and dhammānupassanā
Another aspect of the practice of Vipassanā meditation is exploration of mental reality. As body cannot be experienced without the sensations that arise within it, similarly mind cannot be experienced apart from what its contents - in Pāli, Dhamma. Hence observation of mind (cittānupassanā) and observation of mental contents (dhammānupassanā) are inseparable. When the mind contains craving the meditator realizes this fact. When it is free from craving the meditator realizes this as well. Similarly he realizes when the mind contains aversion or ignorance, and when it is free from these defilements. He realizes when the mind is agitated and scattered, or tranquil and concentrated. This is how he practises cittānupassanā.

The meditator simply observes objectively whatever happens within the mind, whatever mental phenomenon, whatever Dhamma; this is the practice of dhammānupassanā. Without becoming upset, he accepts whatever the mind contains at this moment: craving or aversion, sloth and torpor or agitation, guiltiness or sceptical doubts. And the law of nature is such that by observing them objectively, one automatically eradicates these hindrances. The meditator also accepts when such dhammas arise as awareness, penetrative investigation, effort, joy, tranquility, concentration, and equanimity. And the law of nature is such that as one observes objectively, these wholesome mental qualities are multiplied.

Positive or negative, one simply accepts all mental phenomena. All dhammas arise within the dhammas that it contains. Hence dhammānupassanā and cittānupassanā are inseparable.

Further, the meditator realizes that the mind and mental contents are inextricably linked to the body. The mind is constantly in contact with the physical structure; whatever dhammas arise within it have the base not of mind alone but also of body. This physical aspect of mental events is easily apparent when strong emotions or agitation arise, but is exists as part of every mental phenomenon. Even the slightest passing of thought manifests not in the mind alone but in the combined field of mind and matter; that is, it is accompanied by a sensation within the body.

For this reason awareness of physical sensations is essential for the observation of mind and mental contents. Without this awareness, the exploration of mental reality will be imcomplete and superficial.

All that happens within this mental and physical phenomenon manifests as bodily sensation. Every moment there is a contact of mind and matter at the subtlest level, and from this contact sensation arises. By means of sensation one can experience directly every aspect of the phenomenon of oneself. Therefore, not only kāyānupassanā and vedanānupassanā but also cittānupassanā and dhammānupassanā must be practised by observing bodily sensations.

And as the meditator does so he realizes, "Such is the mind, and such is all that it contains: impermanent, ephemeral, dissolving, changing every mement!" This is not a dogma that he accepts on faith alone, not merely the result of logical deduction, not an imagination or the fruit of contemplation. The meditator realizes the truth for himself directly by experiencing and observing bodily sensations.

Thus sensation becomes the base for the exploration of the entire world of mind and matter. Exploring in this way, the meditator comes to understand truth in all its aspects, the whole truth of oneself. This is sampajañña, the fullness of understanding; this is satipaṭṭhāna, the establishing of awareness. This is how to develop wisdom that will be unshakable, because it arises from a realization of the entire truth.

Observation of sensation leads the meditator to experience the ultimate truth of matter, mind, and mental contents: changing every moment. Then transcending the field of mind and matter, one comes to the ultimate truth which is beyond all sensory experience, beyond the phenomenal world. In this transcendent reality there is no more anicca: nothing arises, and therefore nothing passes away. It is a stage without birth or becoming: the deathless. While the meditator experiences this reality, the senses do not function and therefore sensations cease. This is the experience of nirodha, the cessation of sensations and of suffering.

In this way a Vipassana meditator practises all four satipaṭṭhānas by observing the sensations that arise within the body. He realizes directly the changing nature of body and mind, and as he continues the exploration within, at last he comes to the truth- first within the field of mind and matter, and then in the field beyond. This is how dhammānupassanā is practised completely. This is how the four satipaṭṭhānas are properly practised. This is how one’s meditation, one’s exploration of truth comes to frution.

Come, oh meditators! With the help of bodily sensations let us explore the entire truth of ourselves, and by doing so let us achieve the final goal of real happiness, real peace.