Pantheism is the perception that spirit and divinity dwell within the world rather than apart from it. As the Roman historian Tacitus said of the Germanic tribes, “Their holy places are the woods and groves, and they apply the names of deities to that hidden presence which is seen only by the eye of reverence.” The invisible, spiritual world is not somehow separate from the visible, tangible world, but instead exists “in its heart,” to borrow the words of the French philosopher Maurice Merleau-Ponty. To put it another way: the visible world is the flesh of the invisible gods.
Nowadays, the Norse gods and goddesses are often described as being “the god of this or that,” but this easily leads to the misinterpretation that the gods exist outside of these things and merely control them from a distance. A more accurate way of speaking about them would be to say that, for example, Thor is not “the god of thunder,” but rather the god thunder. This is not merely symbolism, nor is it an attempt to “explain natural phenomena” in a “pre-scientific” idiom. It’s an account of the direct experience of the storm as a personal and divine force.
This can probably be best understood through contrasting it with the dominant strains of Christian theology. In most varieties of Christianity, as we all know, God lives in a remote Heaven and teaches his followers to scorn “earthly cares.” The world is an artifact that he created rather than a part of his being. As 1 Kings 19 says,
And, behold, the Lord passed by, and a great and strong wind rent the mountains, and brake in pieces the rocks before the Lord; but the Lord was not in the wind: and after the wind an earthquake; but the Lord was not in the earthquake: And after the earthquake a fire; but the Lord was not in the fire: and after the fire a still small voice.
Here, God is totally incorporeal, and addresses the prophet Elijah only as a disembodied voice that speaks in a human language – just like the words of the Bible itself. For a pantheist, by contrast, the whole world is a revelation, a “scripture” that anyone can “read” to understand the divine.
More than that: the whole “miracle” of Jesus’s descent to earth, death, and resurrection is dependent on this absolute split between the material and the spiritual. A pantheist would find nothing miraculous or even out-of-the-ordinary in a god assuming bodily form, because all bodily forms are manifestations of divinity. From such a perspective, the idea of salvation is unnecessary and even ridiculous; we are already wholly divine and wholly immersed in divinity. Whereas Christians commune with Jesus in a particular ritual where specially consecrated bread and wine become his body, a pantheist communes with his or her gods all the time, with every breath, every piece of food, and every mosquito bite.
If you enjoyed this article, check out my book on the worldview at the heart of Norse mythology, The Love of Destiny: The Sacred and the Profane in Germanic Polytheism.
 Tacitus, Cornelius. 1948. The Agricola and Germania. Translated by Harold Mattingly. p. 109.
 Merleau-Ponty, Maurice. 1968. The Visible and the Invisible. Edited by John Wild, translated by Alphonso Lingis. p. 150.