Sentence:  Most books on the philosophy of <WSD>religion</WSD> try to begin with a precise definition of what its essence consists of. ... I shall not be pedantic enough to enumerate any of them to you now. Meanwhile the very fact that they are so many and so different from one another is enough to prove that the word “<WSD>religion</WSD>” cannot stand for any single principle or essence, but is rather a collective name. 
Meaning of the word marked with <WSD> tags:  Belief in a spiritual reality (often including at least one deity), accompanied by practices or rituals pertaining to the belief.