The definition, ideas, and general explanation of concepts in this post are derived from the work of Roy Clouser. I have, however, filtered it through my own interpretation and sprinkled in some of my own thoughts on the question. Anything coherent, obvious, reasonable, and logical should be attributed to Clouser. Anything incoherent, absurd, unreasonable, and illogical should be credited solely to me.
Ludwig Wittgenstein believed that the proper task of philosophy was to make the nature of our thought and talk clear. The problems of philosophy were illusory, he believed, and arose as a misunderstanding about language. While I think he greatly overstated the case, I think Wittgenstein was on to something important. Many problems—not only in philosophy but in other areas such as religion—result from the imprecise use of language. A prime example is the debate about what constitutes a “religious belief.”
What exactly makes a belief a religious belief? In order to make that determination we must first define the term in such a way that it is neither too broad nor too narrow by listing all of the features that are true of all religious beliefs and true only of religious beliefs.* While this may appear to be an obvious point, we are often surprised to find what has been pruned when a definition is stripped to its essential components. Imagine, for instance, trying to define the concept of tree in a way that is limited to what is true for all trees but only true of trees. Paring the explanation down in such a manner would not only be difficult but would leave us with a curious, and likely unsatisfying, definition.
What is true of trees will be equally so for religious beliefs. After we cut away the foliage and underbrush that are features of specific religious beliefs we are likely to be unimpressed by the bare, slender reed that remains. We should also expect to find that a minimally precise definition will have exposed the fact that some beliefs that we might have considered to be religious really are not, while finding that others are actually more religious than we might have imagined. Nevertheless, while we might be surprised, unsatisfied, or unimpressed, the important point is that we have defined the term correctly.
Let us begin by examining two features that are commonly (though mistakenly) believed to be essential to religious beliefs:
Religious beliefs require a belief in God or gods
One of the most common misconceptions about religious belief is that it requires a belief in God or a supreme being. But such a feature would be too narrow because it would exclude polytheistic religions that do not recognize a supreme being. In fact, we cannot include the concept of god or gods at all since some religions (e.g., Brahmin Hinduism, Theravada Buddhism) are literally atheistic.
Religious beliefs are beliefs that induce worship or worship-related activities
This feature is also defeated by the counterexamples of Brahmin Hinduism and Theravada Buddhism, neither of which practices worship. The same is true for the religious beliefs of some ancient Greeks such as Aristotle and later the Epicureans who thought the gods neither knew about nor cared about humans. They certainly felt no obligation to worship such apathetic beings.
Having excluded gods and worship from our definition, we are left with very few features that all religious beliefs could possibly share in common. As philosopher Roy Clouser asks, “What common element can be found in the biblical idea of God in Judaism, Christianity and Islam, in the Hindu idea of Brahman-Atman, in the idea of Dharmakaya in Mahayana Buddhism, and the idea of the Tao in Taoism?” The answer, he argues, is that every religious tradition considers something or other as divineand that all of them have a common denominator in the status of the divinity itself.
While many religions disagree on what is divine, they all agree on what it means to be divine . The divine is simply whatever is unconditionally, nondependently real; whatever is just there. By contrast, everything nondivine ultimately depends for existence (at least in part) on whatever is divine. This idea of nondependence or its equivalent is the shared feature in all religious beliefs.
Clouser uses this common element to formulate a precise definition: A belief is a religious belief provided that it is (1) a belief in something as divine or (2) a belief about how to stand in proper relation to the divine, where (3) something is believed to be divine provided it is held to be unconditionally nondependent.
The conclusion we can draw from this definition is that everyone holds, consciously or unconsciously, a religious belief. For many of us, this will be as obvious as finding that our entire lives we’ve been speaking in prose. Others, though, will have a reaction similar to those who argue that while everyone else may speak with an accent, they themselves do not.
Although it may be true that not everyone has a religion (a system of religious beliefs, practices, and rituals), it would be rather absurd to believe that there is anyone who does not have a religious belief . This can be shown by focusing on a theory or belief that many people mistakenly believe to be the reverse of religion: materialism.
Although the idea of materialism has been around since at least the ancient Greeks, it has only recently been considered to be a non-religious idea. This is rather odd considering that it explicitly claims that matter (or some other physical entity) is unconditionally, nondependently real and draws conclusions about nature and humanity based on that belief.
Materialism, in fact, fits the definition more closely than some related beliefs, such as atheism. Just as monotheism claims that the number of gods is one and polytheism holds the view that the number is more than one, atheism simply claims the number of gods is zero. Because it merely takes a position on a nonessential element of religious belief, it would be erroneous to claim that atheism is inherently a religious belief. Materialism, on the other hand, fits the definition in a categorical and clear-cut manner.
Clouser’s definition is neither too broad nor too narrow, is applicable to every known religious tradition, and is logically forceful. Still, I don’t suspect materialists to bend to its logic and admit that they too have a religious belief. When pressed on this point many materialists tend to resort to special pleading or wrangling over the semantics of using the term “religious.” But as Clouser says, “If you insist that whatever you believe to be divine isn’t religious for you, you’ll have to admit that for those of us who hold such a belief and admit its religious character, your belief is going to appear to be religious for reasons that are far from arbitrary.” In other words, call the belief what you want—it certainly looks and functions like a religious belief.