Ancient Jewish philosophy
Philosophy in the Bible
Rabbinic literature sometimes views Abraham as a philosopher. Some have suggested that Abraham introduced a philosophy learned from Melchizedek; Some Jews ascribe the Sefer Yetzirah "Book of Creation" to Abraham. A midrash describes how Abraham understood this world to have a creator and director by comparing this world to "a house with a light in it", what is now called the argument from design. Psalms contains invitations to admire the wisdom of God through his works; from this, some scholars suggest, Judaism harbors a Philosophical under-current. Ecclesiastes is often considered to be the only genuine philosophical work in the Hebrew Bible; its author seeks to understand the place of human beings in the world and life's meaning.
Philo of Alexandria
Philo attempted to fuse and harmonize Greek and Jewish philosophy through allegory, which he learned from Jewish exegesis and Stoicism. Philo attempted to make his philosophy the means of defending and justifying Jewish religious truths. These truths he regarded as fixed and determinate, and philosophy was used as an aid to truth, and a means of arriving at it. To this end Philo chose from philosophical tenets of Greeks, refusing those that did not harmonize with Judaism such as Aristotle's doctrine of the eternity and indestructibility of the world.
Dr. Bernard Revel, in dissertation on Karaite halakha, points to writings of a 10th-century Karaite, Jacob Qirqisani, who quotes Philo, illustrating how Karaites made use of Philo's works in development of Karaite Judaism. Philo's works became important to Medieval Christian scholars who leveraged the work of Karaites to lend credence to their claims that "these are the beliefs of Jews" - a technically correct, yet deceptive, attribution.