The debate on God has a long, venerable history. Yet no single work of philosophy or theology set the kind of milestone that René Descartes’s Meditations on First Philosophy set in the seventeenth century. Descartes broke with the Aristotelian and Christian traditions in several ways, but one of them stands out as the most ground-breaking intellectual development in how people theorized about God: instead of assuming that God exists, or instead of believing that God exists as an article of faith, Descartes asks: could the existence of God be proven to withstand the most systematic, stringent process of doubting a reasonable human being could submit her beliefs to?
Descartes answers in the positive, but that doesn’t matter. More important is the fact that he set a new kind of standard in theological thinking: that God’s existence could and, therefore should, be proven by rational means alone. Theists have taken up the task since then and implemented it variously.
What is perhaps more surprising is that atheists, by and large, have bought into this construal of the debate as a categorical matter: one either can be an atheist, a theist, or otherwise suspend belief as an agnostic. This is because God’s existence can either be proven or disproven by rational means and what is left to determine is which side is right. Atheists, nowadays, overwhelmingly portray themselves as having full certainty for their beliefs, much alone, but in contradistinction to their thesis counterparts. They sell a brand of atheism as fully supported by the a priori or scientific evidence, or else fully supported by the lack of evidence for theism.
But this brand of atheism has unfortunately eclipsed a moderate, tenable, and ultimately much more plausible and rationally warranted kind of atheism that, as far as I can see, is rarely espoused. That is what I call probabilistic atheism, which might be stated as follows:
Given the evidence, I am more confident (but not fully certain) that God does not exist than that he/she does exist.
This position, is of course, different from the position which states with maximum certainty that God exists. It is also subtly different from the position that God is more likely to not exist than to exist. The latter states with full certainty a categorical belief: that God is unlikely to exist. On the other hand, the former, probabilistic atheism, states with less than full certainty a non-categorical belief, a belief that has less than full degree of certainty. The content of probabilistic atheism is also different, and it is in fact the same as that of garden variety atheism, namely that God does not exist. Really what sets them apart, then, is the weakening of the attitude, of the belief, with which the atheistic proposition is believed.
I do not hope to give anything like a full-fledged defense of probabilistic atheism here. But the most common reason atheists cite in support of their position, that is, the absence of (empirical) evidence for the existence of God, does not quite support atheism. It supports agnosticism at best, when it comes to categorical beliefs. But once we open the door to a graded understanding of our belief system, it seems that the overwhelming radio silence of the divine is good grounds for betting against, rather than in favor of it.
The rejection of the Cartesian specter promised by this position is, first of all, great PR for atheists of all stripes. Full certainty is more like a chimera that is just too demanding epistemologically. Most people cannot state any beliefs that they hold with absolute certainty. Surely, there are beliefs that most of us cling to with an emotional attachment, because either we really want them to be true or cannot imagine our lives if they were not true. But setting side such considerations for a moment, one is always able to raise reasonable doubts against most beliefs: what if you are dreaming? or are in the matrix? or the victim of an evil genius? And so on.
Relinquishing the strict epistemic demands of categorical beliefs is not just easier, it is a lot more moderate, realistic. most of the stuff we believe, we believe probabilistically. We believe that the sun is more likely than not to rise tomorrow, than there will not be an earthquake in a week, that our partner will continue to love us in a month from now, etc. Probabilistic belief is the natural habitat, the true home of the human mind. Beliefs about God need to be couched here, not in the inhospitable Cartesian terrain, home only to abstruse academic philosophy.
