The title of this article sounds like it includes a contradiction. How can a person be Jewish or Christian and disbelieve in God? Isn’t the belief in a Creator the foundation of any religion?
Today, the fact is that many people identify as “Jewish atheists” or even “Christian atheists.” One reason is that Jewish identity is not only a “religious” identity, but first and foremost a “national” or “ethnic” belonging. Many Jews who reject formal religion or even disbelieve in God altogether still identify as Jews for national, historical, and cultural reasons. Some atheists of Christian background similarly recognize the strong influence of Christian thought, tradition, and culture in their own lives and therefore continue to identify as “Christian.”
When the idea of a “Jewish atheist” is raised, the first name that comes to mind is usually Baruch Spinoza, a famous philosopher of the seventeenth century. According to the Stanford Encyclopedia of Philosophy, “Spinoza is one of the most important philosophers—and certainly the most radical—of the early modern period.... [His ideas] lay the foundations for a strongly democratic political thought and a deep critique of the pretensions of Scripture and sectarian religion. Of all the philosophers of the seventeenth century, perhaps none have more relevance today than Spinoza.”
In other words, Spinoza is one of the most significant thinkers in terms of modern democracy and also criticism of “sectarian religion” – i.e., the constant conflicts between different interpretations of ultimate truth and attempts to prove the superiority of one denomination or religion over another (part of which I treated in a previous article - Which is the "True" Faith? Judaism vs. Christianity). Spinoza tried to construct a system of thought on completely rationalist bases, which eventually led him to assert that “Except God, no substance can be or be conceived” and therefore everything in the entire universe is a kind of manifestation of “God.” But by “God” he did not mean a personal being, but rather "whatever is in existence," and so religious people condemned him for his belief in “God existing in only a philosophical sense.”
Spinoza was excommunicated from his native Sephardic Jewish community of Amsterdam in 1656 for “abominable heresies.” Yet he went on to become one of the most influential philosophers in European history. On the one hand, Spinoza's work reveals some of the pitfalls of too great a faith in logic and rationality to solve all the questions of human existence. Yet on the other hand, he poses major challenges to “sectarian religion” – or any faith-based system of thought that thinks its own interpretations are superior to all others. Spinoza’s writings are a clarion call for believing people to clarify and reexamine their own views, reject flawed interpretations, and be willing to learn from other perspectives. Because his views were so thought-provoking, many Jewish communities today proudly claim this atheistic thinker as a “Jewish philosopher,” despite the fact that he was excommunicated!