So, what kind of problems can we encounter when our faith is founded upon reason? I mean this post to deal with apologetics - i.e. rational arguments for the faith. In my experience an excessive reliance intellectual arguments can lead to theological problems, and even the loss of faith altogether.
In the early Church, one apologist was Justin Martyr. I believe that he was just a little too fond of philosophy. In some ways, this philosophy laid the foundation of the Arian heresy. St. Justin's ultimate error, in my opinion, was his claim that the Logos was emitted/begotten as an act of will by the Father. The Arian tendencies in this should be readily apparent--the Arians said that there was a time when the Son was not even though they also stated he "began" before time--though Justin's Logos Christology is not really Arian.
If we follow St. Justin's reasoning we can see he is reasoning like a Stoic, who had all kinds of logos theories. Basically, St. Justin does believe the Logos is eternal, but he was not always distinct. The stoics had an odd view of "logos". They believed in an imminent logos which did not become distinct until the thought goes out as a word. This is the intellectual framework Justin used for his apologetics - i.e. his attempt to argue with the intellectuals of his day for the truth of Christianity--which he considered the best philosophy. Basically, Justin postulated an imminent logos within God who became distinct when God, as an act of will, began to create. This is the "Logos Christology" which was ultimately abandoned by the Church. In my opinion, St. Justin's Logos Christology was a product of his intellectual environment and not Apostolic Doctrine.
One of Justin's predecessors was Theophilus:
Theophilus to Autolycus II.X
For he that is created is also needy; but he that is uncreated stands in need of nothing. God, then, having His own Word internal within His own bowels, begat Him, emitting Him along with His own wisdom before all things. He had this Word as a helper in the things that were created by Him, and by Him He made all things.
The logos is not distinct when the logos is internal, the Logos is in the bowels of God. The Logos is not dynamic unless and until the Father emits the Logos along with wisdom and begins to create "all things".
Being dynamic and distinct is a key component of personhood in orthodox triadology, so this doctrine at least implies there was a time when the person of the Logos was not. Now, it is possible that Theolophilus didn't actually believe that the Logos is not a person, but by using the philosophical categories of Stoicism he claimed what I believe is a heretical doctrine of the Logos.
If we allow the Logos is eternal as Justin does, but attempt to describe what kind of eternality the Logos has, we can begin to see how Justin could maintain both an emitted Logos and an eternal Logos. When God began to create, he spoke--the Logos became distinct where before the Logos was not distinct. This is the temporal generation the Catholic Encyclopedia found "unfortunate"
It is, of course, to Christian revelation that Justin owes his concept of the distinct personality of the Word, His Divinity and Incarnation; but philosophic speculation is responsible for his unfortunate concepts of the temporal and voluntary generation of the Word, and for the subordinationism of Justin's theology. It must be recognized, moreover, that the latter ideas stand out more boldly in the "Apology" than in the "Dialogue."
Here St. Justin spells out this Stoic doctrine of the Logos. For the Stoics, the Logos of God was the Logos endiatheos until God speaks, when the Logos is the Logos Spermatikos.
For He can be called by all those names, since He ministers to the Father’s will, and since He was begotten of the Father by an act of will; just as we see happening among ourselves: for when we give out some word, we beget the word; yet not by abscission, so as to lessen the word. When we utter a thought, the utterance of it does not diminish the power of thought in us, though in one sense the thought has gone away from us. [which remains] in us, when we give it out: and just as we see also happening in the case of a fire, which is not lessened when it has kindled [another], but remains the same; and that which has been kindled by it likewise appears to exist by itself, not diminishing that from which it was kindled.
And here we see St. Justin on the subordination of the Logos to the Father, in part due to his Logos Christology:
Dialogue with Trypho, a Jew 56
Then I replied, “I shall attempt to persuade you, since you have understood the Scriptures, [of the truth] of what I say, that there is, and that there is said to be, another God and Lord subject to the Maker of all things; who is also called an Angel, because He announces to men whatsoever the Maker of all things—above whom there is no other God—wishes to announce to them.” And quoting once more the previous passage, I asked Trypho, “Do you think that God appeared to Abraham under the oak in Mamre, as the Scripture asserts?
Temporal generation leads to an Arian sounding heresy all because of the requirements of a philosophical school. As I stated, St. Justin is using a Stoic doctrine of the Logos to describe how the Son was generated. It is an act of volition for the Logos to be generated--as St. Justin says, we do it the same way more or less. This is so because unless God speaks, the Logos is not distinct. Furthermore, being the Logos is generated; he is in a sense "another God and Lord subject to the Maker of all things". Stated another way, there was a time the person of the Logos was not--not the way Arius stated things, but consistent with St. Justin's reasoning as a stoic, and when the person of the Logos is, he is a distinct and subordinate God.
And that this power which the prophetic word calls God, as has been also amply demonstrated, and Angel, is not numbered [as different] in name only like the light of the sun but is indeed something numerically distinct, I have discussed briefly in what has gone before; when I asserted that this power was begotten from the Father, by His power and will, but not by abscission, as if the essence of the Father were divided; as all other things partitioned and divided are not the same after as before they were divided: and, for the sake of example, I took the case of fires kindled from a fire, which we see to be distinct from it, and yet that from which many can be kindled is by no means made less, but remains the same.
Here "numerically distinct" is not meant in the orthodox Trinitarian sense, but in the stoic sense of an imminent logos becoming an external, distinct Logos. As I pointed out, this means a temporal generation of the Son, which I think is a heresy.
Now, in my opinion St. Justin was using the scientific language of his time and place--philosophy. He called himself an apologist, and so he attempted to use reason to show the truth of Christianity. Unfortunately, by philosophizing the deposit if faith he fell into errors--the Logos being indistinct within God just like our own logoi are, the Son as a numerically distinct subordinate God. These ideas answer questions which arise in philosophy and not so much in the life of the Christian.
Now that I have given a quick outline of my reading of St. Justin (and I will accept correction if I am shown to be wrong...) here is how I would apply it to our situation today regarding apologetics. Since apologetic arguments are by their nature based upon reason, it is rather easy to substitute our reason and philosophy for what the Apostles actually teach. It is easy, for instance, to have "systematic theology" replace the preaching of the cross, or to have a philosophical notion, such as divine simplicity or essence/energies begin to rule over the rest of our theology instead of starting with the Christ and him crucified. There are a lot of arguments on the web which turn almost completely on abstract notions and have a tangential relationship with apostolic teaching and pastoral concerns. For examples, see: