Atheists and believers have been arguing a lot over whether Einsteinwas an atheist, or a pantheist, or a deist, or something else. Over the course of these Titanic struggles of the mind, it has often been pointed out that Einstein was a great admirer of Spinoza,and that Einstein's remarks on religion often closely resemble those of Spinoza.
It is perhaps somewhat less well-known that Nietzschewas also a big fan of Spinoza. He said that he felt a special kinship with Spinoza, that he felt Spinoza reaching across the centuries to him, one outcast genius to another.
As with Einstein, so too in the case of Spinoza it is debated whether he was a devout Jew, or a pantheist, or an atheist, or something else. Those who argue that he was an atheist point out that the conclusions he draws do not conflict with atheism. I have often pointed out that if Spinoza, or Hobbes, or Descartes, or any other 17th-century European philosopher, had been an atheist and openly, publicly said so, he would've been killed. He probably would've been extensively tortured first, then burned, and his ashes scattered to the winds. The only halfway-safe way to publicly express atheist positions in 17th-century Europe was to imply them between the lines. Some people, from Spinoza's time to the present, have concluded that that was exactly what he was doing: announcing his atheism by repeatedly, deliberately, systematically hinting at it. Pointing out that this and that and the other reality did not necessarily require certain traditional religious belief in order to be understood. Suggesting various novel ways to understand that which we mean when we say "God." Leaving certain points vague enough that it could lead some people to speculate that the positions he was advancing were atheist. And some people did, right away, and some people have ever since.
As I said, this approach was only halfway safe. Spinoza was excommunicated from the Amsterdam synagogue for it. I have not yet been able to find out any specific ways in which excommunication altered Spinoza's life. But it's hard for me to believe that some of his social connections weren't cut, at the very least.
Spinoza died in 1677. Nietzsche was born in 1844, and Einstein in 1879, which meant that neither of them ever had to fear any criminal proceedings for expressions of atheism. Nietzsche's atheism was pronounced to the point that he declared that even debating the existence of God was beneath an atheist's dignity. (He said that atheists before him had not understood this, which seems to imply that he may have thought that atheists of his own time, or serious ones, at least, no longer condescended to such silly debates. I think he was over-optimistic, and I wish that more atheists would at least consider whether debating the existence of God lends theists a credibility they no longer deserve.)
Einstein's remarks about religion tend to parrot Spinoza, without seeming to consider that Spinoza may often have been unclear for the sake of his life. I don't see the need for such unclarity, such vagueness in Einstein's case. I can only explain it by assuming that Einstein himself didn't really know whether he was an atheist, or a pantheist, or something else. And if I'm right about that then it's perfectly absurd for other people to argue about it. If I'm right, the debate can never be resolved.
Einstein ought to be read more for the sake of physics. If half of the time and effort which is currently expended debating Einstein's religious view were dedicated instead to studying what he had to say about physics, that would be a great leap forward in the education of the general public. As would it be if people devoted half the effort now spent on examining Darwin's and Dawkins' views on religion to seeing what they have to say about evolutionary biology. Between the three of them, Einstein, Darwin and Dawkins, I have yet to encounter one profound sentence on a subject related to religion. It's such a waste on the part of atheists to get bogged down in this, and all the more so when the wisdom of some others on religious topics, people such as Goethe and Marx and Schopenhauer and Nietzsche and Freud and Russell, is so boundless.