I think of philosophy of the art of words and ideas, just like literature is generally the art of words and stories. But, for historical reasons, many people and most philosophers claim philosophy is much more than this.
Spinoza was convinced he was "engaged in the pursuit of truth", as the article writes, and he probably thought he had built a logical proof of the existence of god. But his concepts are fuzzy, so his reasoning is unprovable, and his apparent rigorousness is not at all scientific. Many philosophers disagree with his theories, and none of them are wrong or better or worse than Spinoza, since there is no way to refute or evaluate philosophy.
Apart from these points (proof, progress, consensus), there are many indices for classifying philosophy among the arts. No one would claim to be an expert of a philosopher without reading and studying his book and articles. But, if the substance was more important than the form, it should not matter. One can master Gauss' mathematics or Einstein's physics without reading the original works.
Spinoza was convinced he was "engaged in the pursuit of truth", as the article writes, and he probably thought he had built a logical proof of the existence of god. But his concepts are fuzzy, so his reasoning is unprovable, and his apparent rigorousness is not at all scientific. Many philosophers disagree with his theories, and none of them are wrong or better or worse than Spinoza, since there is no way to refute or evaluate philosophy.
Apart from these points (proof, progress, consensus), there are many indices for classifying philosophy among the arts. No one would claim to be an expert of a philosopher without reading and studying his book and articles. But, if the substance was more important than the form, it should not matter. One can master Gauss' mathematics or Einstein's physics without reading the original works.