It would be perfectly possible for this human soul with all its content to make use of a differently formed body, just as the message from Berlin to Paris could be sent by means other than the electric telegraph. The electric telegraph merely happens to be the most convenient way of sending messages, given the conditions of our present existence, and in the same sense the body with its possibility of movement and the head above provides the most convenient means, in the conditions of our existence on Earth, for the soul to express itself. But it is simply not the case that the body as such has anything more directly to do with the life of the soul than the electric telegraph with its mechanism has directly to do with the transmission of a communication from Berlin to Paris, or a watch with time. It would be possible to devise an instrument quite different from our watches for measuring time. Similarly it is possible to conceive of a body — quite different from the one we use in the conditions prevailing on Earth — that would enable the soul to express itself. […] It is quite conceivable that if, instead of living on the Earth, we were born on some other planet, our soul would be adapted to a quite different planetary existence. The particular formation of our eyes and ears is not attributable to the soul but to the conditions prevailing on the Earth. All we do is to make use of these organs. If we make ourselves consciously aware of the fact that with our soul we belong to the world of the stars, we shall have taken a first step towards a real understanding of our relationships as human beings and our true human nature.
Source: Rudolf Steiner – GA 141 – Between Death and Rebirth – Lecture Three – Berlin, 3rd December 1912
Translated by E. H. Goddard & D. S. Osmond