 On the meaning of philosophy for Philo, see see the supplement on  The Meanings of Philosophy in Philo of Alexandria.  His five philosophical works are De providentia 1 and 2, De animalibus, De aeternitate and Quod omnis probus. The two latter works are the only ones for which we have Greek texts. With the exception of a few rare references to the Bible, these texts could well have been written by a pagan philosopher. This is why some scholars thought they were products of Philo’s paideia, his classical Greek education. Today, there is a tendency to believe that Philo’s extant texts were written near the end of his life. If this is the case, the reason for writing, in the atmosphere of great cultural and political rivalry of the epoch, could have been to demonstrate that a Jew was as able to compose a philosophy as “pure” as any Greek. In any case, the most discussed problem today is the skepticism regarding the authenticity of the De aeternitate, the treatise in which we find the most explicit references to philosophy and philosophers. Since Runia’s seminal article in 1981, a majority of scholars seems to have distanced themselves from thinking the text is inauthentic. For Runia, there is no contradiction in the fact that Philo goes against the biblical tradition and defends the eternity of the world not only in the future but also in the past. The second part of Philo’s treatise, now lost, would have contained the refutation of this unorthodox—at least from a Jewish point of view—thesis. It is probable that Philo, who seems to have had good knowledge of skeptical methods, was trained to argue both pro and contra of a thesis, a dialectical technique of which the De aeternitate is probably the best illustration. We will return to the question of the authenticity in the supplemenary document  About the De aeternitate and the De providentia.