At the time of death, the individuality does not get dissolved, though the physical constituents may be separated and dissolved. What is it that takes rebirth? It can not be the body, because it is discarded and it is dissolved into the physical elements of which it is composed. It cannot also be the Atman, because the Atman is a Universal Presence which cannot be said to be subject to transformation of any kind, such as transmigration. What else does transmigrate?

The peculiar thing called the individual is neither the body nor the Atman. It is a strange admixture of localised self-affirmation in terms of space and time, and this principle of self-affirmation is impossible to define except as a peculiar pressure-point or force which is generated by the influence of space-time upon consciousness which by itself is indivisible, This point of pressure spatio-temporally occasioned is in fact the centre of what is known as the psyche, often called the mind, sometimes known as the Chitta or the Antahkarana, in the Sanskrit language.  

This pressure of consciousness causing the individual self-sense may be broadly understood as having three levels of empirical expression, viz., the conscious, the sub-conscious and the unconscious. Only the conscious level operates when a person is awake, the sub-conscious operates in dream, and the unconscious in deep sleep. The conscious impulses and activities of the individual are limited expressions of the desires which seek to fulfil themselves by way of contact with sense objects. When the pressure of desires is too much and they cannot be easily fulfilled under conditions prevailing in the waking state, they operate as reveries in dream as a sort of satisfaction of strong impulses incapable of operation during waking state. But the desires of an individual are so immense and complicated that their satisfaction cannot be really achieved in a single life. Such unfulfilled longings get wound up in unconscious states, a specimen of which is deep sleep. It is the power of unfulfilled desires that acts like a projectile and drives like a rocket this complex known as the individual pressure-point in the direction of manufacturing a new apparatus for their fulfilment under expected conditions, this new apparatus being called the newly formed body. Here is the interesting background of what is known as rebirth.

As a realised soul has no desires, it has no rebirth. Hence the passing away of an ordinary person and the disappearance of a person like Lord Krishna have nothing in common. The energies which are elemental that go to contribute to the formation of a new body in the case of an individual with unfulfilled desires do not operate in the case of a realised soul, because rebirth is caused by the magnetic pull exerted by the desiring centre of consciousness upon the physical elements, the forces of Nature outside. Such a desire being absent in realised souls, they have no rebirth. They merge into Universal Being. The legacy which acts as the link between the here and the hereafter is desire, which causes reincarnation. The legacy so-called is a mysterious admixture of consciousness and desire, which is the causative factor behind rebirth. It is neither the physical body formed of the five elements, nor the Atman which is all-pervading. It is not true that in death the apparatus through which thinking and feeling act is destroyed; it continues in spite of the body being destroyed. The screen of the television which projects the picture of individuality is the point of consciousness-desire, explained above, and it is not destroyed when the body is destroyed. It is true that in a way, our waking life is also a reflection of some other anterior existence, which we do not remember now, since we are now in this world in a different space-time continuum, totally different from the space-time complex of the previous life. It has to be reiterated that death does not destroy the link between this life and the other life, because death is only of the physical body, and everyone knows well that a person is not exhausted by the physical frame only. There is something more in man than what appears to the eyes, or to any sense organ.

The modern theory of evolution from matter to plant, from plant to life, from life to mind and from mind to intellect is but a corroboration of there being a continuous link from one state of life to another. Else, there would be no evolution and there would be no meaning in any form of life at all.

The theory of karma, or the principle of reaction, which conditions the notions of good and bad etc., is not supposed to apply to the sub-human species since they do not have the self-consciousness of personal agency in action and are just guided by the natural forces of evolution. Suffering cannot be attributed to an individual as long as it is free from personal agency in action. The sub-human species evolve in the same way as there is rise of life from matter to the vegetable kingdom, etc., as mentioned. This is not caused by karma, but by the very pressure of universal evolution.