Christians as early as the first century A.D. attempted to incorporate Greek philosophical ideas with their own theology in order to "speak the same language," as it were, as those Christian evangelists would spread the Gospel of Jesus Christ to Greek philosophers. Paul does this in Acts 17:28 and, more to the point, John explicitly uses the Stoic understanding of Logos in John 1:1, "In the beginning was the Logos, and the Logos was with God, and the Logos was God." The text almost invariably translates Logos as "Word" into English. Nevertheless, this translation does not exclude the understanding of the Stoics, whose understanding of the Logos constituted a central tenet of Stoicism, which was arguably the philosophy of John's day.
For the Stoics, as well as for the Christians who attempted to converse with them, the Logos is simply that which orders the cosmos. The Stoics, like the early Christians, understood the Logos to be found. The difference was that the Stoics believed the Logos existed imminently and as part of the cosmos, whereas the Christians had a more nuanced understanding. Nevertheless, there is clearly a place for common ground to be shared, as the above definition of Logos should illustrate. What, then, is the argument for the Logos, and are there any reasons to think the Logos is God? First, here is an argument for the existence of the Logos:
1. Everything that exists most likely has an explanation of its existence, either in the necessity of their own nature or in an external cause. (Premise, modest version of the PSR)
2. If an ordered cosmos exists and has an explanation of its existence, that explanation is the Logos. (Premise)
3. An ordered cosmos exists. (Premise)
4. Hence, the ordered cosmos most likely has an explanation. (From 1 and 3)
5. Therefore, that explanation is the Logos. (From 2 and 4)
The reader will notice a few things about the above argument. First, I have slightly weakened the Principle of Sufficient Reason (PSR) from a universal to high probability. Secondly, this argument resembles the Leibnizian Cosmological Argument (LCA). Finally, but perhaps easily overlooked, is that the Logos could be found within the necessity of the universe's own nature (Stoicism), or in an external cause (Christianity). The argument above leaves that matter entirely open. So what does atheism have to do with any of this?
An atheist can and should, in my opinion, entirely embrace the concept of the Logos as essential to any knowledge we could possibly have. Apart from order, there is only chaos, and there is no knowledge in the absence of order. The atheist, if he decides to do so, will almost undoubtedly choose to say that the order of the cosmos is found in the necessity of the cosmos' own nature. What is the cosmos, after all, other than bound by logical and mathematical principles, even in the most alleged chaotic states? It appears inescapable that the atheist should take the side of the Stoics.
Now, what else can we know about the Logos other than it is that which orders the cosmos? The atheist should concede at least three things: the Logos is eternal (existing at all times), omnipresent (existing at all places), and indestructible. This is because there is no time or place, even in the future, at which the laws of logic and mathematics will fail to be instantiated. The atheist might be a bit cautious at this point, since if this is not God, then it is at least something God-like. However, since I am interested in finding as much common ground between theists and atheists, I don't think this argument should scare anyone away. All of us seek knowledge, and all of us do so while presupposes that there is knowledge to be found. Apart from the Logos, there is no order and, as mentioned before, apart from order there is no knowledge.