What we call a ‘being’, or an ‘individual’, or ‘I’, is only a convenient name or a label given to the combination of these five [aggregates]. They are all impermanent, all constantly changing. ‘Whatever is impermanent is dukkha’ (Yad aniccaṃ taṃ dukkhaṃ). This is the true meaning of the Buddha’s words: ‘In brief the five Aggregates of Attachment are dukkha.’ They are not the same for two consecutive moments. Here A is not equal to A. They are in a flux of momentary arising and disappearing.
‘O Brāhmaṇa, it is just like a mountain river, flowing far and swift, taking everything along with it; there is no moment, no instant, no second when it stops flowing, but it goes on flowing and continuing. So Brāhmaṇa, is human life, like a mountain river.’ As the Buddha told Raṭṭhapāla: ‘The world is in continuous flux and is impermanent.’
One thing disappears, conditioning the appearance of the next in a series of cause and effect. There is no unchanging substance in them. There is nothing behind them that can be called a permanent Self (Ātman), individuality, or anything that can in reality be called ‘I’. Everyone will agree that neither matter, nor sensation, nor perception, nor any one of those mental activities, nor consciousness can really be called ‘I.’ But when these five physical and mental aggregates which are interdependent are working together in combination as a physio-psychological machine, we get the idea of ‘I.’ But this is only a false idea, a mental formation, which is nothing but one of those 52 mental formations of the fourth Aggregate … , namely, it is the idea of self (sakkāya-diṭṭhi).
These five Aggregates together, which we popularly call a ‘being’, are dukkha itself (saṃkhāra-dukkha). There is no other ‘being’ or ‘I’, standing behind these five aggregates, who experiences dukkha. As Buddhaghosa says :
‘Mere suffering exists, but no sufferer is found;
The deeds are, but no doer is found.’
There is no unmoving mover behind the movement. It is only movement. It is not correct to say that life is moving, but life is movement itself. Life and movement are not two different things. In other words, there is no thinker behind the thought. Thought itself is the thinker. If you remove the thought, there is no thinker to be found. Here we cannot fail to notice how this Buddhist view is diametrically opposed to the Cartesian cogito ergo sum: ‘I think, therefore I am.’