Both Bruno and Spinoza had challenged the traditional lens of science and the natural world in their own ways. These two philosophers, however, being of different times, were not mutually affiliated with each other. This meant that both were similar with regards to their arguments against the established philosophies espoused by the prevailing traditional religious dogma, but they were different in how they had approached their critiques. Bruno philosophically had rejected many traditional notions elaborated by the church, from heliocentrism to the progression of classical philosophy, to his flirtations with pantheism. He was accused of being a heretic by the Roman Catholic Church. Giordano Bruno was at the centre of controversy throughout his life as a prodigious member of the religious caste that had come to be known as the intellectual upper class in the Renaissance Era of Europe. Spinoza, similarly, was excommunicated from his Dutch Jewish community, with his works still considered taboo in Orthodox communities to this day.
Heliocentrism was a major pillar of Bruno’s separation from the church when he came to opposition against the Aristotelian-Ptolemaic concept of geocentrism. With consistency, Bruno comes to agreement with much of the dissenters of the Ptolemaic conception of geocentrism, and wrote works in support of philosophers and cosmologists who had opposed the established church orthodoxy which had derived much of its beliefs in cosmology from the Ancient Greeks. This would be best demonstrated in Bruno’s support of Copernicus, as his works would demonstrate a foundation for the further rejection of the established Aristotelian cosmological doctrine. This fundamental opposition to the church would play a key part of the larger philosophy that Bruno had had. The logical conclusion of his belief in heliocentrism would be his belief in pantheism. Similar to Spinoza, Bruno had developed a belief in God as an embodiment of the Universe, an object of awe and wonder, and supposedly “aesthetic delight”. They share in their conceptions of the absolute as not just transcendent, but also immanent. Even as they were moving Europe in the direction of a more rationalistic philosophy, they were also sanctifying the natural world. However, it is also important to note that Bruno’s works take this point even further than Spinoza’s ideas, suggesting that the universe itself is divine, a sort of embodiment of the Absolute.
Although Spinoza was born after Bruno died, it is not likely that the former would have read the latter, but it is certainly more possible that they were reading some of the same well-known literature at the time. However, some scholars have thought that Spinoza is following Bruno, or interestingly enough, accuse Bruno of being Spinozist, as an insult to his philosophy, given that it would be ahistorical to say that Bruno copied Spinoza. From this, we can see that they reasoned their way to some similar conclusions despite coming from different backgrounds (Jewish vs. Catholic), as Western philosophy at the time did share certain schools of thought influenced by the mixing of the Greek and Abrahamic traditions, as well as a similar historical context (the Renaissance). Spinoza has left a long legacy and has a reputation for being someone not just against religious dogma, but opening the floodgates for the questioning of the fundamentals of faith with his work on biblical hermeneutics and criticism. Although he never explicitly endorsed atheism in his writings, it was not an uncommon accusation launched at him by contemporaries. On the other hand, Bruno, although challenging church doctrines, remained steeped in a mystical and magical tradition, which shaped his entire worldview.
Spinoza was significantly different in approach and the end goal from Bruno however. Despite challenging the religious institutions of their times, and both having been controversial for their opposition to the established doctrines, they had very different end goals. Bruno had sought for a fundamental reorientation from an interpretation of philosophy as though it was a singular, coherent progression from one ancient philosopher to the other, to one that incorporated holistically the philosophical tenets of ancients before Aristotle. Bruno’s Christianity was far more of an esoteric concept than any of his other religious counterparts, but had held strong enough that it would seem rather that his controversy came from the strength of his beliefs. Spinoza, on the other hand, simply had a different philosophy. Rather than oppose the traditional religious dogma on religious grounds, Spinoza challenged the orthodoxy as a whole, and brought several completely different interpretations of the universe that were divorced from religious or historical foundations.
Ultimately, their metaphysics and cosmology can be strikingly similar at times, with both identifying nature/the universe as not separate from God or first cause. Both also don’t hold a rigid distinction between laws of nature and things ordered by God, seeing them as parts of one greater whole, or rather two ways of defining the same thing. Nature is associated with metaphysics, not just physics, and human reason is advocated as a good way to go about both. Studying both philosophers is an interesting look into how both were simultaneously products of their historical context and shapers of the one to come.