It seems characteristic of many books addressing philosophical, or "enlightened", paganism in the Roman Empire to describe it as a mere precursor to Christianity, or to criticize its proponents as being inconsistent by continuing attachment to ancient pagan beliefs and rituals. By philosophical or enlightened paganism I refer to Stoicism, Cynicism, Platonism or Neo-Platonism, and other philosophical schools prevalent in the empire prior to the advent of Christianity. Christian authors, even recent Christian authors, generally profess to admire this kind of pagan thought but are at pains to criticize it in some fashion because it is undeniably heathen--i.e. pre-Christian.
It seems to me that those who claim this kind of paganism merely "prepared the way" as it were for Christianity encounter problems because it can be maintained just as easily that Christianity is in many ways simply derivative of this kind of paganism, just as it is in many ways derivative of less enlightened paganism, having borrowed so much of its dogma and ritual from various religions circulating in the empire before Christianity became, in effect, the imperial state religion.
Those who assert that the enlightened pagans betrayed themselves by their willingness to follow the ancient rituals, or were somehow inexplicably compelled to do so despite the wisdom of their other beliefs, encounter similar problems. These assertions typically contrast the enlightened beliefs with the supposedly silly anthropomorphic simplicity of ancient beliefs and rituals. However, it would seem that the figure of Christ is inherently anthropomorphic, if not the ultimate in anthropomorphic theism, as at once human and divine. And, the enlightened pagans tended to justify their adherence to ancient rituals as signs of devotion to aspects of the divine which were merely represented by the various gods and goddesses, but which formed a single unity (not unlike, it would seem, the doctrine of the Trinity and devotion to the saints).
It's difficult not to see this tendency on the part of certain authors as defensive and disingenuous. It doesn't make much sense to deny the colossal debt Christianity owes to the pagan beliefs prevalent in the empire (not to mention its Jewish origins) at the time of its spectacular growth, although this would seem to be necessary given its claim to exclusiveness and its nature as a revealed religion.
One also finds the somewhat inconsistent view that philosophical paganism failed because it was insufficiently anthropomorphic; that it was left for Christianity, as the true religion, to combine the need for a human religion with the philosophical abstractions said to be needed for truly enlightened thought.
I think it's likely, though, especially as we reconcile ourselves to our disappointingly small place in the universe, that we'll find ourselves more and more attracted to religions which emphasize the non-human characteristics of the divine. The "enlightened" pagans may have had the right idea after all.