Deism is the philosophical belief in a deity based on reason rather than religious revelation or dogma. It was a popular perception among the "philosophes", who adopted deistic attitudes to varying degrees. Deism, in this respect, is very different from atheism, which denies the existence of a deity altogether. Voltaire, for instance, was convinced that the existence of god was a demonstrable fact. The deistic god, however, often bore little resemblance to the God of Christian scripture, which meant that deists were often heavily criticized by the adherents of confessional faiths and could be accused of atheism. Deists often pushed for religious toleration, a move which would have supported the open expression of atheism. This is not because they supported atheism—they did not—but because deist philosophers tended to be in favour of the civil freedom of conscience. As Michael J. Buckley writes, "If atheism was unacceptable, superstition and fanaticism were even more so." Deists were not pro-atheist, but their anticlerical leanings indirectly benefited the evolution of atheism. In historiographical terms, it has been quite common to see a close link between deism and atheism. Buckley critiques Peter Gay's view of the direct tie between deism and atheism, writing, "the vectors which Gay charts are certainly there, but the distinction may be somewhat too neat, too overdrawn." Louis Dupré describes deism as "the result of a filtering process that had strained off all historical and dogmatic data from Christian theology and retained only that minimum which, by eighteenth-century standards, reason demands." Atheism is perhaps the same process taken a step further. Buckley credits the rise of atheism with the gradual submission of theology to philosophy—as thinkers, including church leaders, began to argue religion on philosophical terms, they opened the way for disbelief—they made atheism thinkable. Deism is, in this perspective, a complicated waypoint on the path to atheism: deism is the philosophical belief in a deity based on reason. Once belief in God is based on reason, it becomes thinkable to reason one's way into disbelief. Freemasons in continental Europe during the Enlightenment era were accused of atheism. The masonic "Constitutions" of 1723 are vague on the matter of religion, stating that if a Freemason "rightly understands the Art, he will never be a stupid Atheist, nor an irreligious Libertine", while also asking that he follow "that religion to which all men agree, leaving their particular opinions to themselves".