431. Consequently the animal beings are expressing those I's who have come so far in development that they have emerged from the direct fire-zone. They have advanced so far that they are able to control fire with "feeling-energy". Their whole corporeal organism is maintained entirely by the power of a specially determined balance of tension between "gravity" and "feeling" energies. This tension is expressed directly through that which we call a being's "normal temperature". With reference to differences in this "normal temperature" there is a special analysis of this point shown later on in "Livets Bog". Here we will just mention that the differences occur because the individual is able to use the two opposing energies in the daily manifestations of his being. The fact is that his ability to lift his hand or move his foot is due entirely to the effect of the will on that condition of tension which will thereby shift to one side or the other, to the advantage of either "gravity-energy" or "feeling-energy", thus causing the instability we call "movement". This principle is active in every physical situation. There would be no way whatsoever of manoeuvring the physical organism if there were not a certain instability between "gravity-energy" and "feeling-energy". Every function of the organism, indeed, absolutely all movement in the Universe is, in actual fact, due to instability between these two energies.
      It is, of course, obvious that this "juggling" between "gravity-energy" and "feeling-energy" will be primitive in the I's first spiral zone. This is actually maintained here only through transferred automatic functions from mineral and plant life in a previous spiral. That this "juggling" must necessarily become more and more perfected over time, until it is at last quite masterly, is of course a forgone conclusion considering the I's eternal structure and its growing ability to make use of the other important basic energies or sources of power, that is "intelligence", "intuition" and "memory", in this processing of heat and cold.