The Buddha discovered the truth of all phenomena. He knew the
characteristic of each phenomenon by his own experience. Out of compassion he
taught other people to see reality in many different ways, so that they would have a deeper understanding of the phenomena in and around themselves. When realities are classified by way of paramattha dhammas (absolute realities), they are classified as: citta, cetasika, rupa, nibbana. 

Citta, cetasika and rupa are conditioned realities (sankhara dhammas). They
arise because of conditions and fall away again; they are impermanent. One
paramattha dhamma, nibbana, is an unconditioned reality (visankhara
dhamma); it does not arise and fall away. All four paramattha dhammas are
anatta, not self. 

Citta, cetasika and rupa which are conditioned realities, can be classified by way of the five khandhas. Khandha means 'group' or 'aggregate'. They are: 

                 1.   Rupakkhandha, which are all physical phenomena. 
                 2.  Vedanakkhandha, which is feeling (vedana). 
                 3.  Sannakkhandha, which is perception (sanna). 
                 4.  Sankharakkhandha, comprising fifty cetasikas. 
                 5.  Vinnanakkhandha, comprising all cittas. 

The fifty-two kinds of cetasika are classified as three khandhas: a cetasika
which is feeling (vedana) is classified as one khandha, the vedanakkhandha; a
cetasika which is perception (sanna) is classified as one khandha, the sannakkhandha; as regards the other tiny cetasikas, they are classified all together as one khandha, the sankharakkhandha. For example, in sankharakkhandha are included the following cetasikas: 'intention' (cetana), attachment (lobha), aversion (dosa), ignorance (moha), lovingkindness (metta), generosity (alobha) and wisdom (panna). Sankharakkhandha is sometimes translated as 'activities' or ‘mental formations'. 

As regards citta, all cittas are one khandha: vinnanakkhandha. The Pali terms
vinnana, mano and citta are three terms for the same reality: that which has the
characteristic of knowing or experiencing something. When citta is classified as
khandha the word vinnana is used. Thus, the five khandhas are grouped as one
rupakkhandha, and four namakkhandha. Three namakkhandhas are fifty-two
cetasikas; the other namakkhandha is eighty-nine or one hundred and twenty-one cittas. 

Nibbana is not a khandha; it is void of khandha (in Pali: khandha-vimutti). 

The ‘visuddhimagga' (XX,96) explains about the arising and falling away of
nama and rupa: 

                 There is no heap or store of unarisen nama-rupa 
                 (existing) prior to its arising. When it arises it does 
                 not come from any heap or store; and when it ceases. 
                 it does not go in any direction. There is nowhere any 
                 depositor in the way of a heap or store or hoard of 
                 what has ceased. But just as there is no store, prior 
                 to its arising, of the sound that arises when a lute 
                 is played, nor does it come from any store when it 
                 arises, nor does it go in any direction when it ceases, 
                 nor does it persist as a store when it has ceased, but 
                 on the contrary, not having been, it is brought into 
                 being owing to the lute, the lute's neck, and the man's 
                 appropriate effort, and having been, it vanishes - - so 
                 too all material and immaterial states (rupa and nama), 
                 not having been, are brought into being, having been, 
                 they vanish.

The khandhas are real; we can experience them. We experience
Rupakkhandha when, for example, we feel hardness. It does not stay;  it arises
and falls away. Not only rupas of the body, but the other physical phenomena are rupakkhandha as well. For example, sound is rupakkhandha; it arises and falls away, it is impermanent. 

Vedanakkhandha (feeling) is real; we can experience feelings.
Vedanakkhandha comprises all kinds of feeling. Feeling can be classified in
different ways. Sometimes feelings are classified as threefold: pleasant feeling,
unpleasant feeling, neutral feeling. 

Sometimes they are classified as fivefold: pleasant feeling, unpleasant feeling
and indifferent feeling, bodily pleasant feeling, bodily painful feeling. 

Bodily feeling is feeling which has body-sense, the rupa which has the capacity
to receive bodily impressions, as condition. The feeling itself is nama, but it has
rupa (body-sense) as condition. When an object contacts the body-sense, the
feeling is either painful or pleasant; there is no indifferent bodily feeling. When
the bodily feeling is unpleasant it is akusala vipaka (the result of an
unwholesome deed), and when the bodily feeling is pleasant it is kusala vipaka
(the result of a wholesome deed). 

Since there are many different moments of feeling arising and falling away it is
difficult to distinguish them from each other. For instance, we are inclined to
confuse bodily pleasant feeling which is vipaka and the pleasant feeling which
may arise shortly afterwards together with attachment to that pleasant bodily
feeling. Or we may confuse bodily pain and unpleasant feeling which may arise
afterwards together with aversion.

When there is bodily pain, the painful feeling is vipaka, it accompanies the
vipakacitta which experiences the object impinging on the body-sense.
Unpleasant (mental) feeling may arise afterwards; it is not vipaka, but accompanies the akusala citta. It arises because of our accumulated dosa (aversion). Though 'bodily' feeling and 'mental' feeling are both nama, they are entirely different kinds of feelings, arising because of different conditions. When there are no more conditions for dosa there can still be bodily painful feeling, but there is no longer (mental) unpleasant feeling. The arahat may still have akusala vipaka as long as his life is not terminated yet, but he has no aversion. 

We read in the 'Kindred Sayings' (I, Sagatha-vagga, the Marasuttas, Ch. II, par.
3, The Splinter): 

                      Thus have I heard: The Exalted One was once 
                       staying at Rajagaha, in the Maddakucchi, at the 
                       Deer-preserve. Now at that time his foot was injured 
                       by a splinter. Sorely indeed did the Exalted One feel 
                       it, grievous the pains he suffered in the body, keen 
                       and sharp, acute, distressing and unwelcome. He truly 
                       bore them, mindful and deliberate, nor was he cast 
                       down.... 

Feelings are sixfold when they are classified by way of the six doors: there is
feeling which arises through the eyes, the ears, the nose, the tongue, the
body-sense and the mind. All these feelings are different;  they arise because of
different conditions. Feeling arises and falls away together with the citta it
accompanies and thus at each moment feeling is different. 

We read in the 'Kindred Sayings' (IV, Salayatana-vagga, Part II, Kindred
Sayings about Feeling, par. 8, Sickness II) that the Buddha said to the monks: 

                      …Monks, a monk should meet his end collected 
                      and composed. 
                      This is our instruction to you. 

                      ...Now, monks, as that monk dwells collected, 
                      composed, earnest, ardent, strenuous, there arises in 
                      him feeling that is pleasant, and he thus understands: 
                      'There is arisen in me this pleasant feeling. Now that 
                      is owing to something, not without cause. It is owing 
                      to this contact. Now this contact is impermanent, 
                      compounded, arisen owing to something. Owing to 
                      this impermanent contact which has so arisen, this 
                      pleasant feeling has arisen : How can that be permanent?' 
                      Thus he dwells contemplating the impermanence in 
                      contact and pleasant feeling, contemplating their 
                      transience, their waning, their ceasing, the giving of 
                      them up. Thus as he dwells contemplating their 
                      impermanence..  the lurking tendency to lust for contact 
                      and pleasant feeling is abandoned in him. 

                      So also as regards contact and painful 
                      feeling...contact and neutral feeling.... 

There are still many more ways of classifying feelings. If we know about
different ways of classifying feelings it will help us to realize that feeling is only a
mental phenomenon which arises because of conditions. We are inclined to cling to the feeling which has fallen away instead of being aware of the reality of the present moment as it appears through eyes, ears, nose, tongue, body-sense or mind. In the passage of the 'Visuddhimagga' which was quoted above (XX, 96) nama and rupa are compared to the sound of a lute which does not come from any 'store' when it arises, nor goes in any direction when it ceases, nor persists as a 'store' when it has ceased. However, we cling so much to feelings that we do not realize that the feeling which has fallen away does not exist any more, that it has ceased completely. Vedanakkhandha (feeling) is impermanent. 

Sannakkhandha (perception) is real; it can be experienced whenever we
remember something. There is sanna with every moment of citta. Each citta
which arises experiences an object and sanna which arises with the citta
remembers and 'marks' that object so that it can be recognized. Even when there
is a moment that one does not recognize something citta still experiences an
object at that moment and sanna which arises with the citta 'marks' that object.
Sanna arises and falls away with the citta; sanna is impermanent. As long as we
do not see sanna as it really is: only a mental phenomenon which falls away as
soon as it has arisen, we will take sanna for self. 

Sankharakkhandha (the fifty cetasikas which are not vedana or sanna) is real; 
it can be experienced. When there are beautiful mental factors (sobhana
cetasikas) such as generosity and compassion, or when there are unwholesome mental factors such as anger and stinginess, we can experience sankharakkhandha. All these phenomena arise and fall away: sankharakkhandha is impermanent. 

Vinnanakkhandha (citta) is real; we can experience it when there is seeing,
hearing, smelling, tasting, receiving impressions through the body-sense or
thinking. Vinnanakkhandha arises and falls away;  it is impermanent. All
sankhara dhammas (conditioned phenomenal), that is, the five khandhas, are
impermanent. 

Sometimes the khandhas are called the 'groups of grasping' (in Pali:
upadanakkhandha). The upadanakkhandhas are the khandhas which are the
objects of clinging. Those who are not arahats still cling to the khandhas. We take the body for self; thus we cling to rupakkhandha. We take mentality for self; thus we cling to vedanakkhandha, to sannakkhandha, to sankharakkhandha and to vinnanakkhandha. If we cling to the khandhas and if we do not see them as they are, we will have sorrow. As long as the khandhas are still 'objects of clinging' (upadanakkhandha) for us, we are like people afflicted by sickness. 

We read in the 'Kindred Sayings' (III, Khandha-vagga, the First Fifty, par. I,
Nakulapitar) that the housefather Nakulapitar, who was an old, sick man, came
to see the Buddha at Crocodile Haunt in the Deerpark. The Buddha said to him
that he should train himself thus:  'Though my body is sick, my mind shall not be sick. ' Later on Sariputta gave him a further explanation of the Buddha's words: 

                      Herein, housefather, the untaught many-folk... who 
                      are unskilled in the worthy doctrine, untrained in the 
                      worthy doctrine - - these regard body as the self, they 
                      regard the self as having body, body as being in the 
                      self, the self as being in the body. 'I am the body', 
                      they say, 'body is mine', and are possessed by this 
                      idea; and so, possessed by this idea, when body alters 
                      and changes, owing to the unstable and changeful nature 
                      of the body, then sorrow and grief, woe, lamentation 
                      and despair arise in them. They regard feeling (vedana) 
                      as the self… They regard perception (sanna) as the 
                      self... They regard the activities (sankharakkhandha) 
                      as the self… They regard consciousness (vinana) as 
                      the self… That, housefather, is how body is sick and 
                      mind is sick too. 

                      And how is body sick, but mind not sick? 
                      Herein, housefather, the well taught ariyan disciple... 
                      regards not body as the self… He regards not feeling 
                      (vedana) as the self... He regards not perception 
                      (sanna) as the self... He regards not the activities 
                      (sankharakkhandha) as the self... He regards not 
                      consciousness (vinnana) as the self... As he is not so 
                      possessed, when consciousness alters and changes 
                      owing to the unstable and changeful nature of 
                      consciousness, sorrow and grief, woe, lamentation and 
                      despair do not arise in him. Thus, housefather, body 
                      is sick, but mind is not sick. 

As long as we are still clinging to the khandhas we are like sick people, but we
can be cured of our sickness if we see the khandhas as they are. The khandhas
are impermanent and thus they are dukkha (unsatisfactory). We read in the
'Kindred Savings' (III, Khandha-vagga, Last Fifty, par. 104, Suffering) that the
Buddha taught the 'Four Noble Truths' to the monks. He said: 

                 Monks, I will teach You dukkha, the arising of 
                 dukkha, the ceasing of dukkha, the way leading to the 
                 ceasing of dukkha. Do you listen to it. 
                 (In the English translation 'dukkha' is sometimes 
                 translated as 'suffering', sometimes as'ill. 
                 Here the English text has the word 'suffering'.) 

                 And what, monks, is dukkha? It is to be called the 
                 five khandhas of grasping. What five?  The 
                 rupakkhandha of grasping, the vedanakkhandha of 
                 grasping, the sannakkhandha of grasping,  the 
                 sankharakkhandha of grasping,  the vinnanakkhandha 
                 of grasping. This, monks, is called dukkha. 

                 And what, monks, is the arising of dukkha? It is 
                 that craving... that leads downward to rebirth... the 
                 craving for feeling, for rebirth, for no rebirth... This, 
                 monks, is called the arising of dukkha. 

                 And what, monks, is the ceasing of dukkha? It is 
                 the utter passionless ceasing, the giving up, the 
                 abandonment of, the release from, the freedom from 
                 attachment to that craving... 

                  This, monks, is called the ceasing of dukkha. 
                  And what, monks, is the way going to the ceasing 
                  of dukkha? 

                 It is this Ariyan Eightfold Path… This, monks, is the 
                 way going to the ceasing of dukkha.

As long as there is still clinging to the khandhas there will be the arising of the
khandhas in rebirth, and this means sorrow. If we develop the Eightfold Path we
will learn to see what the khandhas really are. Then we are on the way leading to
the ceasing of dukkha, which means: no more birth, old age, sickness and death.
Those who have attained the last stage of enlightenment, the stage of the arahat,
will be, after their life-span is over, free from the khandhas. 
 

             1.  Which paramattha dhammas are nama? 
             2.  Which paramattha dhammas are sankhara dhammas (conditioned       realities)? 
             3.  Which paramattha dhamma is visankhara dhamma (unconditioned reality)? 
             4.  Which sankhara dhammas (conditioned realities) are nama? 
             5.  Are all cetasikas sankharakkhandha? 
             6.  Is vedana cetasika (feeling) a khandha? 
             7.  Is sanna cetasika (perception) a khandha? 
             8.  Is bodily painful feeling vipaka? 
             9.  Is mental unpleasant feeling vipaka? 
             10. Which khandhas are nama? 
             11. Is seeing-consciousness a khandha? 
             12. Is the concept 'human being' a khandha? 
             13. Is sound a khandha? 
             14. Which paramattha dhammas are khandhas?