If I were to teach a course on philosophy this would be what I begin with.
One of the most poetic concepts in the philosophy of Spinoza-- and it may encapsulate the meaning of philosophy itself, is amore intellectus, intellectual love. This doctrine conceives of knowledge as itself an affect, philosophy itself a pathos, truth itself a passion. One other philosopher, Schelling, shared this view, or at least expressed it directly, in his wonderful quote: “Only he who has tasted freedom can feel the desire to make over everything in its image, to spread it throughout the whole universe. Anyone who does not come by philosophy on this path merely imitates others with no feeling for why they do as they do.”
But how could this amore intellectus, in the necessarily abstract paths it must follow toward its object, have any conceivable application to life? It is not so difficult to imagine. The mystery of form is the mystery of life-- that is the pathos of philosophy. When we realize in a quote from Homer or a phrase in Chopin some epitome of our own life’s suffering, it ceases to afflict us, or in the figures of Raphael and a definition of Plato’s some image of our own joy, the anxiety of our longing is forever stilled. Form is itself a consolation, form is itself a satisfaction.
Aside from its direct application to life, philosophy serves to enrich the human being. Philosophy, imbued with Eros and transformed into a genuine intellectual love, opens up a distance between the philosopher and the object of this love, truth. It brings man to face what Amiel called “the obscure.”
"The obscure only exists that it may cease to exist. In it lies the opportunity of all victory and all progress. Whether it call itself fatality, death, night, or matter, it is the pedestal of life, of light, of liberty and the spirit. For it represents resistance – that is to say, the fulcrum of all activity, the occasion for its development and its triumph. " – Amiel
This is my view of what philosophy is most essentially.