There are as many ideas of religion as there are societies, perhaps as many as there are people in the world.
The idea is to imagine a state of total religious amnesia, so that we’d all be starting from scratch. If we wiped all religion away, anthropology suggests, it would rapidly reappear in new yet familiar forms—but probably without monotheism, assuming that history is any guide. Religion in the broad sense clearly represents a human instinct, since we find it in all human societies. But we can safely say that there’s no instinct for monotheism as such, since no society ever came up with the idea independently after it first appeared.
There are importantly different approaches to 'definition' that must be taken into account when trying to define anything as complex as religion. Plato was convinced that every word has an essential definition, an essence. He set as his task to try to discover the essence of crucial ideas and concepts such as truth, beauty and justice.
There are a few important family resemblances that identify religion. Albert Einstein, in his essay Religion and Science, suggested that one can experience a "cosmic religious feeling...which knows no dogma" from the sciences and it was not just exclusive to traditional religious structures. Einstein, in his case, talks about a "profound reverence" for the universe as seen through science and he even goes so far in his letter to Hans Muehsam (dated March 30, 1954) to call himself a "religious nonbeliever". Religious belief systems tend to be all-inclusive, subsuming all aspects of the world and the events that occur in it. Belief in the eventual occurrence of a 'judgement', on which occasion human lives will be appraised and suitably rewarded, is also a very frequent, but not universal, component in religious belief systems.
Religion typically involves construing everything that occurs in the world as intentional and , consequently, as the locus of value and purpose. Modern western empirical science has surely been the most impressive intellectual development since the 16th century. Religion, of course, has been around for much longer, and is presently flourishing, perhaps as never before. (True, there is the thesis of secularism, according to which science and technology, on the one hand, and religion, on the other, are inversely related: as the former waxes, the latter wanes. Recent resurgences of religion and religious belief in many parts of the world, however, cast considerable doubt on this thesis.) Religion typically is a prolific source of cultural artifacts, such as music literature, poetry, and theatre, and a dramatic influence on other cultural artifacts, such as science, history and philosophy.
The challenge of different answers to a particular issue is not unique to the topic of religion. For example, you can sit 100 math students down, give them a complex problem to solve, and it is likely that many will get the answer wrong. But does this mean that a correct answer does not exist? Not at all. Those who get the answer wrong simply need to be shown their error and know the techniques necessary to arrive at the correct answer.
