The word "philosophy" comes from Ancient Greece and is a combination of two words--"philos" (loving) and "Sophia" (wisdom), so it literally means "love of wisdom."
There is a difference between claiming to love wisdom and claiming to possess it. Socrates called himself a philosopher, a lover of wisdom, in order to emphasize the difference between his position and that of the "wise men," the sophists, who claimed to possess wisdom.
One has to humble oneself to learn wisdom. The beginning of ones wisdom is a sincere acknowledgement of ones ignorance. Socrates said that we are all ignorant; the only difference is that we are ignorant about different things. He also said, "All that I know is that I know nothing." And, with that statement, he proved to be the wisest person in Athens at that time.
But what is this "wisdom" a philosopher pursues and a sophist claims to possess? It is the ability to know as well as to enjoy "the good life." It is also knowledge about the nature of the universe, a person's place in it, and a person's destiny. In other words, philosophy seeks to answer questions about the meaning of human existence and the kind of life a person should lead.
Answers to these questions have been offered by various mythologies and religions; however, philosophy arose when mythological and theological answers were found unsatisfactory by some deeper than ordinary thinkers.
Criticism of religious beliefs does not make philosophical reflection antireligious; it is just consistent with a philosopher's essential characteristic--that is, critical thinking for oneself.
But what is critical thinking? Before answering this question, I'd like to explore an even deeper one: What is thinking? For me, thinking is an attempt to mentally process perceptions and/or imaginations accurately. Here, I also offer a psychology textbook definition by Gardner Lindzey, Calvin S. Hall, & Richard F. Thompson: "Thinking is an active search for something that the person wants and needs. It reflects a need to explain and to understand, and a desire to create." So, as you can see, by both my and their definitions, it can be argued that just accepting something on faith is not thinking; it certainly is not critical thinking; it's merely believing; it's like using your brain to record rather than to think. It's just "blind faith."