Translating iman as “faith” can lead to confusion. In the English language, faith as a word to describe religious sentiment is often posed against the notion of knowledge. Certain things are simply known and other things are only known “by faith” or through a “leap of/to faith.”
Unfortunately, many Muslims grow up with this secular notion of faith and end up saying things like, “No one can know for sure if God exists — at most we can have faith that he does.” Or, “There is no way to decide which religious claims are true or not. It’s all a matter of personal, subjective faith.” Little do they realize that if this is their “faith,” it is a faith that is a million miles away from iman.
Using the word “belief” also has its pitfalls. Again, secular philosophy draws a sharp distinction between the concepts of “belief” and “knowledge.” Points of belief are on a lower epistemic order than points of knowledge. To know something or to strive to know something is to converge on the truth, but anyone can believe anything about anything. Belief has no necessary connection to the truth. When people think of religion as simply a “set of beliefs,” they subconsciously make that association as well — religion has no necessary connection to truth and reality.
These are some of the very real dangers of uncritically adopting languages and carelessly translating religious concepts into a framework that is foreign to and sometimes completely at odds with them. The way we use words has a major impact on the way we think about the world, God, and ourselves. Just the use of a single word can totally reconfigure the spiritual state of a person or an entire generation.
For comparison’s sake, we should know as Muslims that iman is on a higher epistemic order than the quotidian facts of our lives or any other piece of worldly knowledge. To enter into the fold of iman, one must first testify and bear witness to the truth: La ilaha illa-Allah, Muhammadun Rasulullah. In English, “testifying,” “bearing witness,” “holding these truths to be self-evident,” for example, are closer to the concept of iman than terms like “faith” and “belief.” Not that these latter two should not be used, but their use should come with caveat and clarification.