Is there a God? A quick look at theism, atheism, and pantheism.
Theism is the word we use to describe the belief that God or various gods exist. Any religion which recognizes a God or gods as existing is considered theistic in nature, but there are several subtypes of theism and different ways of viewing what it means. Monotheism is the most widespread type of theistic religion practiced in the West, and is simply a term that means the theist believes that there is only one God. A monotheist can believe that God is a divine intelligent being that has an interest in the universe that can intercede (often referred to as divine intervention), or they can believe that God created the universe but has little or no interest in what actually happens within it. The belief that God has essentially left man to fend for himself is called Deism, and is usually most popular with those who believe God gave man reason, and that it is by reason man should run the world God created for him.
This is in stark contrast to the idea of polytheism, or the belief in many gods. This type of belief system is much more prevalent in the East, where some polytheistic religions are still practiced. It was also the main form most early religions took, the most familiar to the layman being the religions of the Greeks and Romans, which contained a large group of gods, each in charge of various aspects of life and the universe. This collection of Gods within a polytheist religion is called a pantheon. While these familiar examples considered gods divine and immortal, other polytheistic religions downplay the power of gods. Buddhism and Hinduism in particular emphasize that while gods are powerful beings, they are not immortal, and like all things, will eventually perish. While these religions may encourage its followers to worship these gods, it is usually in hopes of pleasing them and receiving divine gifts and favors.
Another type of polytheism is animism, in which gods and spirits reside in nature and inanimate objects. This is the belief that rocks and trees may have souls, or possibly even consciousness, and familiar examples include many Native American Religions and Wicca. It can be argued that animism is its own subclass of pantheism, but because spirits of nature are often revered and worshiped as gods, it is more appropriate to label this as a form of polytheism.
Atheism is the belief that there simply is no God. It is a viewpoint that states that the idea of God or gods is untrue and that the universe and all events that occur within it are the result of purely natural phenomena, not divine will, plan, or intervention. Atheism became increasingly popular as science began to make a great deal of progress in Western culture during the Age of Enlightenment. While early Enlightenment philosophers, such as English philosopher Hume, were all but outcast for making their atheism public knowledge, the stigma against atheism has all but disappeared from the modern world. The reason the rise of science played such an important role in the rise of atheism is that science began to explain things which people traditionally relied on religion to understand. Often its results had a tendency to disagree with the beliefs and dogmas presented by established religions. This led many to the conclusion that these religions must be false, for if God or a set of gods created the universe, surely they ought to know how it worked, yet they demonstrated over and over that they did not. One example of particular potency is the Christian story the creation of the world in comparison to how science describes it. The Christian version has God creating the world and all life in six days, taken to mean that there should be no large gaps in time between the creation of various animal species. Science, however, claims the earth has been forming over the last four billion years, and that life has been slowly evolving over the last several hundred million years. The conflict of these types of stories with scientific knowledge and progress has greatly championed the cause of atheism.
While the compatibility (or lack thereof) between science and religion is another matter for another article, it is worth nothing that atheism on its own does not force its believer out of spiritual practice. For instance, while an atheist may find it highly unlikely that there is a non physical human soul, the lack of the existence of God or gods does not preclude it. An Atheist is free to believe various metaphysical philosophies, in the immortality of the soul, in ghosts, or other paranormal or supernatural ideas. Because science is often the justification for one's atheist belief, and these subjects by their nature fall outside the context of science, it is unusual to find atheists that believe in things like those mentioned above, but because there is no reason to suppose that science is capable of giving a full understanding of everything in the universe (another philosophical argument entirely), an atheist can still hold what might be described as "spiritual" beliefs.
Pantheism is the belief that God does exist, but not as an individual entity separate from the universe, instead stating that the universe IS God. Different from animism in that it does not suppose rocks and trees are God in spirit form, or that the dirt of the earth itself is God (but fully compatible with animism, wherein the spirits of trees and rocks are no more amazing than the spirits within people), it instead states that the totality of the universe is God. Pure pantheism can best be described in terms of an identity relationship. We all know that 1 = 1, and that 5 - 4 = 1. In this way, a pantheist says the universe = God, or God = all things in existence. The idea is that the sum total of the universe is God, and as such, every rock, tree, and human is part of God. The main question to be asked of pantheism is whether or not this God is intelligent or aware. Some pantheists believe that the sum total of the universe actually is an intelligent entity. While this idea may seem confusing at first, look to the human brain for better understanding. If all we could see was one single neuron (similar to how all we can see of the universe is actually very little in comparison to its full totality) it might be impossible to understand or believe that a large enough complex of them could give rise to intelligence. This oversimplifies how the brain gives rise to intelligence and consciousness, but it is a good example of how a pantheist can imagine an intelligent God. There are also pantheists who don't believe God as the Universe is intelligent, but is simply an entity that exists, and we're just lucky enough to have the awareness to appreciate it.
There is another type of pantheism, called panentheism, which differs in that it does not see the universe in an identity relationship with God (God = Universe), but instead believes that the universe is made of God while the concept of God is actually greater than the universe. Instead of God being the sum totality of the universe, the sum totality of the universe is actually just a part of God, and God is more than that. It is possible to hold a panentheist viewpoint along with a monotheistic or polytheistic viewpoint. A monopanentheist, for example, would believe there is one God, and that the universe in which we reside is made of God. Our universe would be a subset of God, or a part of the sum totality of God. Pure panentheism does not have to define itself as either monotheistic or polytheistic, though the idea is so abstract it can be difficult to grasp. The main thing to note is its difference in relation to pantheism, in which everything which exists in sum total is God, where as panentheism says all existence is part of God, but God extends beyond that, making everything in existence within God, but not God itself.