Logical argumentation is the hallmark of philosophy. Philosophy is characteristically dialectical; it consists of reasoned arguments for philosophical views, as well as presentation and consideration of possible opposing arguments (counterarguments). Even when a philosopher such as Thomas Aquinas advocates religious belief, he does so on the basis of reason.
People unfamiliar with philosophy often misunderstand what philosophy is. They confuse philosophy with literature, "wisdom writing", anthropology, mythology, folklore, and even psychology and sociology.
Determining what distinguishes world philosophy from world literature "raises, in an acute form, the question of what philosophy is." This is because some classics of non-Western so-called "philosophy", such as the Mahabharata, are frequently not dialectical; they do not use reasoning and argumentation as the primary method of arriving at conclusions. In fact, they sometimes eschew discursive reason altogether in favor of story-telling.
Are such writings philosophy, then? The question becomes particularly complicated in the area of ethics. Most literate cultures have "classics of practical wisdom" works containing popular proverbs or maxims of practical advice, or important and beautiful allegories or parables of the good life, but no argument. Such works may ground their conclusions in individual feelings and individual religious experiences, both of which are viewed skeptically by most Western philosophy. Or such works may simply be tracts of "advice" pamphlets describing what is prudent. (The analogues in the Western tradition are the works of Marcus Aurelius, Cicero, Montaigne, LaRochefoucauld, etc.) "Where should we draw the line between philosophical ethics and literature with moral dimensions ...?" (ibid)
Most philosophers, Western and non-Western alike, see literature with moral dimensions as literature only, but a few ethics texts include selections from them nonetheless. The majority opinion in philosophy seems to be that works lacking dialectic are not philosophy, but that a primarily literary work might have parts that are philosophy because it discusses philosophical issues in a systematic, analytical way, e.g., the Bhagavad-Gita section of the Mahabharata, or the Grand Inquisitor section of The Brothers Karamazov. "Wisdom writings" (collections of maxims or proverbs) tend to be excluded from ethics texts, in my experience, because they lack argument.
People uneducated in academic philosophy often have trouble distinguishing philosophy from anthropology, mythology, or folklore, which all have as a primary objective to report, catalog, and compare what people believe. The common misunderstanding is that philosophy is just "what you believe". On this view, philosophy is a kind of natural event, like weather; peoples beliefs just are, though they also change over time. Anthropology, mythology, and folklore are like weather reporting. But academic philosophers are much more like meteorologists than weather reporters. Philosophy never takes beliefs at face value. Many people believe patently false and irrational things. Philosophys task, rather, is to put beliefs to the test of critical analysis, to determine which beliefs are well-supported by reason and which are not. Thus, while philosophers are as interested as anybody else in what people happen to believe, they are not like pollsters who simply report peoples beliefs "objectively", without critical analysis.
Philosophers are certainly interested in comparative religion and social science, but philosophy is not exactly an empirical discipline; it is more "applied logic". It analyzes the arguments in support of belief; the analysis checks for ambiguity, inconsistency, invalidity and unsoundness of argument, as well as plausibility and consistency of logical consequences. I enumerate these things because I find much misunderstanding about what it means to "analyze" a belief philosophically. My students (and others) often think "analysis of belief" is providing a psychological or sociological account of it. They think they have satisfactorily refuted a belief if they can "explain it away" by uncovering its psychological or sociological origin (E.g., "So-and-so only says X because so-and-so is a member of such-and-such race or sex or class or ethnic group"). But philosophers would disagree. For philosophers, "explaining away" someones beliefs by psychological or sociological analysis without addressing the content of the belief itself is a paradigm example of the ad hominem fallacy. Psychological or sociological analysis of this kind does not address whether or not X is well-supported by reason, regardless of what race or sex or class or ethnic group its advocates belong to. The philosophers question is: is it rational to believe X?
Folklorists are anthropologists or sociologists who study the traditional customs, tales, and sayings preserved among a people, usually transmitted by oral tradition. Folklore is a comparative science (naturally I mean a social science here); it reports and compares. It conceives of itself as primarily data-gathering, and like social sciences generally, is non-judgmental and non-critical. It does not ask if the beliefs of a people are true or well-supported; that is not its job.
I am bringing up the question of distinguishing philosophy from anthropology, folklore, and other social sciences because much of the information we have about the beliefs of some non-European cultures, particularly African and native American cultures, has been gathered by anthropologists and folklorists. Most of Africa did not have writing until well into the modern period, so much of the information gathered by anthropologists is within the province of folklore. It is important to note that this information by itself is not philosophy. Nor is reporting it. A simple uncritical inventory of beliefs is not a statement of philosophy in the academic sense. Philosophy develops; later philosophical views typically modify, criticize, and enrich earlier views. Oral traditions characteristically do not develop; in an oral tradition, the argument (if any) for a belief does not accompany it, since transmitting the argument along with the belief would make the whole process too time-consuming and the whole package too difficult for most people to understand, let alone remember. In an oral culture, it is a sufficient justification for X to say "We believe X because our ancestors believed it". Only with the introduction of writing in a culture do we find sustained, continuous development of argumentation about traditional beliefs (what academic philosophers would call philosophy).
The foregoing has been an attempt to convey some idea of the methodology of philosophy. Now, what about the content of the beliefs analyzed? Philosophy cant be merely a method, since that definition would be too broad. Scientists, for example, analyze beliefs (about the natural world) using the methods of logic, but nobody (nowadays) would say they are doing philosophy. There is more to philosophy than logical analysis; there are standard topics to which philosophers apply their tools: topics like the existence of God, the nature of reality, the relation between mind and matter, what it means to be a person, the fate of a person after death, and the "law of the deed" (the connection, if any, between ones conduct now and ones destiny). But note that in order to count as philosophy, the approach to these topics must be critical as well as speculative. Joseph Campbells work is often (wrongly) thought to be academic philosophy because it describes and compares beliefs about these topics; but description and comparison are not critical analysis. Religious beliefs are commonly conflated with philosophy, but the religious approach is generally grounded in faith, which is quite different from critical analysis.