226. With reference to what has been described in the present chapter, the physical bodily functions are able to give the individual no experience of knowledge but only of feeling, meaning that form of consciousness which dominates the primary zones of the animal kingdom. Terrestrial mankind differs from the creatures in these zones in that it has the ability not only to experience feelings but also to experience knowledge. While the first form of consciousness is to be expressed as physical, the last, on the other hand, must be expressed as mental. But as terrestrial people's spiritual bodies are only emerging in an embryonic state and thus are chiefly only subconscious, the knowledge they are able to acquire manifests itself likewise in an embryonic state. As terrestrial mankind's supporting body for day-consciousness consists of the physical body and physical senses rooted therein, which all give sensory experience - that is to say physical seeing, hearing, smelling, tasting and sensory impressions in general - it is consequently these sensory experiences that become the basis of the first release in the individual of this dawning mental functioning and the creation of knowledge. This knowledge will thus be the same as the beginning of the unveiling of the physical or material world. But as the material world - according to cosmic analyses - constitutes only an embryonic zone of existence, then terrestrial mankind's knowledge or science, as already mentioned, constitutes merely the outermost periphery of the spiritual world. However terrestrial mankind's science does not remain at a standstill but is under constant development and will at some time come to include not only the spiritual world's outermost periphery but also its very centre; in other words, all the other planes of existence.