I mean that a philosophy is something of a life-image or an image of life, of the world and each person has their own image like that. We all have a general idea, image, context of meaning, thoughts about the world and the future and metaphysical possibilities. Many people’s such image is heavily dependent on religious images and ideas, while for others their own image might be dependent on the influences of materialistic science and cultural critics pushing cynicism and atheism. But we all have a “worldview”. This worldview is, really, a personal philosophy that each person carries around with them.
But to answer your question about how do we identify those who philosophize versus those who do not… actively philosophizing usually (not always) involves an understanding that what you are doing is actively philosophizing. It understands itself as a conscious truth-process. This can manifest as reading books of other philosophers, debating philosophical ideas and questions with other people, writing your own philosophical thoughts down or just sitting and thinking about these things. It doesn’t need to be formalized in terms of participation in academia but of course it can be.
Your interest in Nietzsche, Camus etc. already shows you are actively philosophizing. That is one of the great things about great writers of philosophy: when you read their books you cannot help but begin to actively philosophize yourself. Nietzsche in particular and because of his aphoristic and iconoclastic style, really forces the reader to begin to engage philosophically with the questions and issues he is writing about. An aphorism is a tool to bring the reader into proximity with a question or issue and to sketch something of a map through it, but to then stop there and not give the full answer. Rather even to provoke the reader, to taunt and encourage him to think more deeply and figure it out for himself. Because most good aphorisms present truths in ways that appear paradoxical and self-contradictory or at least in ways that are deliberately obscure and incomplete.
Yes you said there are levels, I agree. Right now you may be thinking about some of these issues because they interest you, and you are reading some books of philosophy. Next you might join a philosophy discussion group or take some philosophy classes at a university. Or you might take it upon yourself to master the knowledge of certain philosophers or certain philosophies. Or next you might start writing your own thoughts down, and eventually contemplate writing your own books of philosophy. Who knows? There is no requirement to do any of that but it can be a fun part of the process as our wisdom and experience grows.
Ultimately if you love the truth for its own sake, that is philosophy. One philosopher I know also talked about the euphoria of reason, relating this to some things Plato wrote about; the euphoria of reason, if you have ever experienced this (I have, many times) is when you feel truly ‘high’ and euphoric-happy, emotionally elevated and truly satisfied and joyous all and only because of thinking. You are thinking about ideas, deep concepts, trying to unravel and to understand, and that sort of pure philosophical THOUGHT by itself, either you sitting on your own or reading a book or talking to another person about these things, is causing you to feel that pure euphoria of happiness and suffusing meaning.
And if you’ve ever experienced THAT then you can be sure you are a philosopher at heart. Because the mind is a substance, a real material substance of a metaphysical nature and not merely some abstraction or mere firing of neurons in the brain. To be a philosopher at heart is to understand this fact implicitly and to happily engage in the construction, refinement and expansion of your own mind as literal truth-substance.
