Just as the Urnanâbhi, a species of spider, creates a thread out of his own body and takes it back, just as the plants grow by their own nature, and all these things are yet separate and apparently different (the heart is, as it were, different from the other parts of a man’s body; the plants are different from the earth; the thread is different from the spider — yet they [the earth, the spider and so on] were the causes, and in them these things act), so from this Unchangeable One has come this universe.

Vivekananda on the  Mundaka Upanishads