Book review: Gersonides – Judaism within the Limits of Reason

The last decade has seen a significant number of books written with the goal of attempting to reconcile contemporary science and the Torah. This is far from a new phenomenon and it in fact goes back to medieval times. Perhaps its greatest proponent was Gersonides (1288-1344), also known as Ralbag (Rabbi Levi ben Gershon).

In Gersonides: Judaism within the Limits of Reason (Littman 978-1906764784), author Seymour Feldman (former professor of philosophy at Rutgers University) has written an enticing overview of the life and thought of one of the greatest and most daring; if not most controversial medieval Jewish philosophers. Like his predecessor Maimonides, Gersonides attempted to reconcile the philosophy of Aristotle with traditional Jewish thought.

In truth, I think it’s unfair to use the term controversial, as often is done when referring to the views of Gersonides, as the term carries with it negative connotations. While his philosophical views may be in the minority, and not universally accepted; as one of the greatest philosophers of his time, his views must be considered.

But unlike Maimonides, Gersonides wrote very few letters and as such, details of his life are scant. Besides a very brief bibliographical overview, Feldman spends all his efforts understanding the man and his worldview.


Feldman writes that unlike many modern scientists or philosophers who either scorn religion or compartmentalize it; Gersonides did not see any fundamental discrepancy between the pursuit of truth via reason, and its attainment through divine revelation. Understanding that there has to be but one divine truth, Gersonides felt it was an imperative that reason and divine revelation must be able to be harmonized.

Reason was something Gersonides took quite seriously. In fact, he saw reason and logic as a divine gift. With that, he felt it was essential that God had to be, and must be understood within the limits of reason.

Tertullian’s notion that credo quia absurdum (I believe because it is absurd) would be an anathema to Gersonides. As a polymath in addition to being an accomplished astronomer, Feldman writes that the study of astronomy and other natural sciences according to Gersonides, were fundamental and prerequisite requirement for the ascent to metaphysics. The reason for this was that Gersonides felt that the whole of nature, even our own bodies, displays the handiwork of the Lord.

In a dense 10 chapters, the book provides the reader with a detailed summary of Gersonides’ worldview in areas such as the Bible, creation, Divine knowledge and omnipotence, prophecy and more.

Gersonides has a number of contentious opinions, and none of it greater than his approach to divine omniscience. Most Jewish philosophers felt that there was complete divine omniscience, of which human free will was simply a perplexing part of. Gersonides took the radical approach and felt that while God knows in advance what choices are available to a person; God in fact does not know what choice the individual will ultimately take.

Gersonides methodology was in part to try to reconcile Aristotle with traditional Jewish philosophy. On this topic, Feldman spends a chapter and writes in detail how Gersonides was almost universally rejected for this approach as detailed in his magnum opus on philosophy Milhamot Ha-Shem (The War of the Lord). One of his opponents mocked it by calling it “Wars against the Lord”. Such mocking was grievous, given the six questions Gersonides was dealing with are fundamental to Judaism; and relevant to this very day.

The book also discusses other non-traditional approaches Gersonides had, including minimizing the notion of miracles, and the approach that a person’s soul is not immortal, rather it’s their intellect that is.

Gersonides didn’t create a formal system of thought, such as Maimonides did in Moreh Nevukhim (The Guide for the Perplexed). And like Maimonides, there are many ways to interpret Gersonides, to which Feldman provides a superb overview of all of Gersonides core ideas.

Feldman shows how many of Gersonides’ doctrines were not traditional. Not being bothered by that, Gersonides never shied away from drawing the logical conclusion from what he considered to be the true philosophical premise.

As interesting as he is provocative, Gersonides: Judaism within the Limits of Reason provides the reader with a comprehensive look at one of the most formidable Jewish philosophers.


About the Author
Senior information security and risk management professional. I speak at industry conferences, and write on information security, social media, privacy and technology. My book reviews are on information security, privacy, technology, and risk management. Here for Times of Israel, book reviews on religion and philosophy.
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