Varieties of pantheism
Despite the broad, inclusive nature of pantheism, modern pantheists generally identify themselves as members of two rather divergent groups:

Classical pantheism, which is expressed in the immanent God of Kabalistic Judaism, Advaita Vedanta Sanatana Dharma, and Monism, generally viewing God in a personal manner.
Naturalistic pantheism, based on the relatively recent views of Baruch Spinoza and John Toland (who coined the term "pantheism"), as well as contemporary influences, and which encompasses key aspects of pandeism.
The vast majority of persons who can be identified as "pantheistic" are of the classical variety (such as Hindus), while most persons who self-identify as "pantheist" alone (rather than as members of another religion) are of the naturalistic variety. The division between the two "flavors" of pantheism is not entirely clear in all situations, and remains a source of some controversy in pantheist circles.

Methods of explanation
An oft-cited feature of pantheism is that each individual human, being part of the universe or nature, is part of God. One issue discussed by pantheists is how, if this is so, humans can have free will. In answer, the following analogy is sometimes given (particularly by classical pantheists): "you are to God, as an individual blood cell in your vein is to you." The analogy further maintains that while a cell may be aware of its own environs, and even has some choices (free will) between right and wrong (killing a bacteria, becoming malignant, or perhaps just doing nothing, among countless others) it likely has little conception of the greater being of which it is a part. Another way to understand this relationship is the Hindu concept of Jiva, wherein the human soul is an aspect of God not yet having reached enlightenment, after which it becomes Atman.

However, it should be noted that not all pantheists accept the idea of free will, with determinism being particularly widespread among naturalistic pantheists. Although individual interpretations of pantheism may suggest certain implications for the nature and existence of free will and/or determinism, pantheism itself does not include any requirement of belief either way. However, the issue is widely discussed, as it is in many other religions and philosophies.


Debate
Some critics argue that pantheism is little more than a redefinition of the word "God" to mean "existence" or "reality". Many pantheists reply that even if this is so, such a shift in the way we think about these ideas can serve to create both a new and a potentially far more insightful conception of both existence and God.

Perhaps the most significant debate within the pantheistic community is about the nature of God. Classical pantheism believes in a personal, conscious, and omniscient God, and sees this God as uniting all true religions. Naturalistic pantheism believes in an unconscious, non-sentient universe, which, while being holy and beautiful, is seen as being a God in a non-traditional and impersonal sense.

Cosmotheism, a small but controversial racialist group which considers itself a form of pantheism, has an evolutionary interpretation of God, seeing him to be impersonal, but not taking a clear stance as to his sentience. (Like the terms “pantheism”, “monotheism”, and “polytheism”, “cosmotheism” was not used in antiquity. The term seems to have been coined by Lamoignon de Malesherbes in 1782 with regard to Pliny the Elder; various scholars have used it since then, but to refer to different sorts of religious belief.)

The viewpoints encompassed within the pantheistic community are necessarily diverse, but the central idea of the universe being an all-encompassing unity and the sanctity of both nature and its natural laws are found throughout. Some pantheists also posit a common purpose for nature and man, while others reject the idea of purpose and view existence as existing "for its own sake."

Related concepts
Panentheism
Pantheism has features in common with panentheism, such as the idea that the universe is part of God. Technically, the two are separate, inasmuch as pantheism finds God synonymous with nature, and panentheism finds God to be greater than nature alone. Some find this distinction unhelpful, while others see it as a significant point of division. Many of the major faiths described as pantheistic could also be described as panentheistic, whereas naturalistic pantheism cannot (not seeing God as more than nature alone). For example, elements of both panentheism and pantheism are found in Hinduism. Certain interpretations of the Bhagavad Gita and Shri Rudram support this view.

Pandeism
Pandeism combines the major elements of natural pantheism with deism (the concept that God created a self-regulating universe, and does not actively intervene in its operations). The fundamental concept is that a single, omnipotent deity preceded the existence of the universe, that this deity envisioned or designed the universe with all of its physical attributes, and that this deity created the universe by completely incorporating itself into the material universe. In short, God ceased to be an independent and sentient God, and instead became the non-sentient and non-responsive universe. This subset of naturalistic pantheism is distinct in that it necessarily encompasses the belief in a sentient deity that existed before the formation of the universe.


Pantheistic concepts in religion
Hinduism
In Hindu theology Brahman is the ultimate, both transcendent and immanent, the absolute infinite existence, the sum total of all that ever is, was, or ever shall be. As the sun has rays of light which emanate from the same source, the same holds true for the multifaceted aspects of God emanating from Brahman, like many colors of the same prism. This concept of God is of one unity, with the individual personal Gods being aspects of the One; thus, different deities are seen by different adherents as particularly well suited to their worship. Pantheism and panentheism are key components of Advaita theology.

In Smartist tradition, which follows Advaita philosophy, Brahman is seen as the one God, with aspects of God emanating therefrom. With all Hindus, there is a strong belief in all paths, or true religions leading to One God.

Some of the Hindu aspects of God include Ganesa, Devi, Vishnu, and Siva.

Hindus who follow the Smarta tradition believe that these different aspects of God can bring worshippers closer to Moksha, end of the cycle of rebirth.

Other subdivisions of Vedanta do not strictly hold this tenet. For example, Dvaita school of Madhva holds Brahman to be only Vishnu. In contrast, Arya Samaj believes in worshipping Brahman directly, without conceptualizing God through form such as Ishta-deva or using an icon, the Hindu murti to focus. Arya Samaj only takes into consideration the formless Brahman while Advaita states that the formless Brahman and the formful God Saguna Brahman are the same and hence worship of either is valid and equivalent. However, Advaita agrees with Arya Samaj that the Ultimate Reality is attributeless, in contrast to the theistic schools of Ramanuja, who also stressed panentheism, and Madhva, an advocate of duality.

Vedanta, specifically, Advaita, is a branch of Hindu philosophy which gives this matter a greater focus. Most Vedantic adherents are monists or "non-dualists" (i.e. Advaita Vedanta), seeing multiple manifestations of the one God or source of being, a view which is often confused by non-Hindus as being polytheistic.

Judaism
The Kabbalah, in Jewish mysticism, paints a pantheistic/panentheistic view of God which has wide acceptance in Hasidic Judaism, particularly from their founder, the Baal Shem Tov.