What is Philosophy

The etymological meaning of the term is: love of wisdom.  The dictionary definition of wisdom is "the quality of having experience, knowledge, and good judgment".  I don't think that is what counts for philosophy in modern times, so let's dig deeper.

Some definitions from Merriam-Webster:

1. all learning exclusive of technical precepts and practical arts
2. a discipline comprising as its core logic, aesthetics, ethics, metaphysics, and epistemology
3. a search for a general understanding of values and reality by chiefly speculative rather than observational means

The first definition is quite interesting as it says that philosophy is the domain of the theoretical, or the impractical.  That is alas no longer true, since now-a-days all "practical" sciences or arts have fields of theory and research behind them.

The second definition was quite true a few centuries back, and is somewhat valid at present if we consider that logic and epistemology are still considered fields of philosophy.  Aesthetics is now part of various artistic disciplines.  Ethics has penetrated more and more into sociology, environmental studies, economics, law, and is now generally studied in relation to specific problems: animal rights, the abortion debate, environmentalism and vegetarianism, etc.  Metaphysics has disappeared from the mainstream, and wondering about space-time, the far universe, other forms of life, the origin of life, the fundamental principles behind physical laws, are all parts of specific sciences now.

The third definition is glaringly wrong since a lot of theoretical scientific research, especially in mathematics and the computational sciences, can be "chiefly" speculative (or rather, abstract) rather than observational.

In my opinion, the most trenchant modern definition of philosophy was provided by the Austrian-British philosopher Ludwig Wittgenstein:

Philosophy aims at the logical clarification of thoughts. Philosophy is not a body of doctrine but an activity. A philosophical work consists essentially of elucidations. Philosophy does not result in 'philosophical propositions', but rather in the clarification of propositions. Without philosophy thoughts are, as it were, cloudy and indistinct: its task is to make them clear and to give them sharp boundaries. (Tractatus Logico-Philosophicus)

Philosophy therefore, if we agree with this, is perhaps better called "applied logic".  It is to turn on the floodlights of one's brain and look closely at a set of propositions and to find out whether they are saying something consistent or contradictory or whether they are, in the final analysis, meaningless.

Regarding the analysis of  religion, metaphysics and spirituality, philosophy teaches us "How to Pass from Disguised Nonsense to Patent Nonsense" (again, Wittgenstein).  It is another matter that the beliefs of a religion should not be analysed too much by someone who needs it.  Beliefs mostly serve a purpose which is more emotional than logical.

Analyses of religion and spirituality is best left to nihilistic heathens.