During phases of the historical process symbols which are given special significance and power in a revealed religion through the revelation itself can gradually lose their efficacy, either partially or completely, as a result of the weakening of the spiritual basis of that religion, as can be seen in the case of the de-mythologizers of our day. Nevertheless, the symbols of nature are permanent and immutable. What the sky signifies symbolically, as for example the dimension of transcendence and the Divine throne (‘arsh), to use the Islamic image, is as permanent as the sky itself. The sun symbolizes the Universal Intellect as long as it goes on shining and the tree with its extended branches is a symbol of the multiple states of being as long as trees grow on the surface of the earth. That is why one may speak of a cosmologia perennis, of a qualitative science of nature which is always valid and which reveals an aspect of nature which is, to say the least, no less real than the changing aspect studied by modern science. The main difference between the traditional and modern sciences of nature lies in the fact that modern science studies change with respect to change, whereas traditional science studies change in the light of permanence through the study of symbols which are nothing but the reflection of permanence in change.