Philosophers are no more free from biases than us mere mortals. For instance, it seems that a philosopher’s personality actually makes them preferentially choose one view of “Free Will” over another — (Schultz, Cokely and Feltz, 2011: Journal of Consciousness and Cognition). See Adam Feltz’s great discussion of their paper on “Experimental Philosophy“.
It has always been obvious to me that Atheists’ choose philosophical views to cuddle their personality too. Theologians likewise construct theological cathedrals to protect their personalities. We are all silly in our certainties. But few suspect that their temperament potentially colors their philosophy. But as my diagram below illustrates, this should not be surprising. After all the same truth-defective brain acts on our thoughts about philosophy, politics, religion, diet, morality, medicine and more.