Why did Christianity not follow Philo of Alexandria's definition of logos? Philo of Alexandria (20 BC – 50 AD), a Hellenized Jew, used the term Logos to mean an intermediary divine being, or demiurge. Philo followed the Platonic distinction between imperfect matter and perfect Form, and therefore intermediary beings were necessary to bridge the enormous gap between God and the material world. The Logos was the highest of these intermediary beings, and was called by Philo "the first-born of God." Philo also wrote that "the Logos of the living God is the bond of everything, holding all things together and binding all the parts, and prevents them from being dissolved and separated."

So why did the Christian view not follow this definition and instead make the leap to describing logos as part of God?
From the works of Philo we can see how he saw the logos, or word/wisdom directly and try to compare a bit with Plato and with Christ.


  But the divine word which is above these does not come into any visible appearance, inasmuch as it is not like to any of the things that come under the external senses, but is itself an image of God, the most ancient of all the objects of intellect in the whole world, and that which is placed in the closest proximity to the only truly existing God, without any partition or distance being interposed between them: for it is said, “I will speak unto thee from above the mercyseat, in the midst, between the two cherubim.”25 So that the word is, as it were, the charioteer of the powers, and he who utters it is the rider, who directs the charioteer how to proceed with a view to the proper guidance of the universe. (The works of Philo, p330)


The logos is the 'divine word' and 'most ancient of all the objects of intellect' (see quote from Philo above). This does seem similar to some degree to the archetype idea of Plato which are the 'true objects' of life. Basically those philosophers back then tried to identify with words the intelligence of nature that one saw beyond the physical object. This essence, idea or thought, or whatever was 'something' and here we find Philo associating it with 'God's image' or shadow of his person.  But it does not seem exactly to be a person necessarily.

Here is another quote from Philo about the logos:


  And even if there be not as yet any one who is worthy to be called a son of God, nevertheless let him labour earnestly to be adorned according to his first-born word, the eldest of his angels, as the great archangel of many names; for he is called, the authority, and the name of God, and the Word, and man according to God’s image, and he who sees Israel. (147) For which reason I was induced a little while ago to praise the principles of those who said, “We are all one man’s sons.”43 For even if we are not yet suitable to be called the sons of God, still we may deserve to be called the children of his eternal image, of his most sacred word; for the image of God is his most ancient word. (The works of Philo,


From Philo's words above it does start to seem that the logos is possibly a person, if we take his reference to 'the great archangel' literally. Then again its not really clear as he reverts back to the 'image' theme as the thing really meant.  Maybe that 'image' is just personalized a bit to be a sort of prime archangel symbolically. Philo does not make it clear that he sees the logos as an actual person.

So what is the big difference between this view and the Apostle's?  This is kind of obvious.  If we look at Philo's logos, it is a force or being available to all who live in accordance with it, and in that sense is a 'mediatory' between man and God. This, one could say, is in some sense a confused, shadowy admission that God has a mediator he sends to the world, who is very ancient. However Jesus was much more then this.  Jesus was an intermediator, and the word sent from God but also a 'sacrifice'.  The logos of Philo does not intend to sacrifice himself (or itself) in order to reconcile the world to God.

On the other hand, the divinity of Christ, is not a concept derived from Philo's logos, or a leap from it. Philo's logos is principally incomplete and rejected as as being a biblical truth by Christians due to its low perception of a mediator without a sacrifice.  The trinity, or with respect to the Christian 'logos', the divine eternal nature of the Son, co-equal with the Father and Spirit, is something stemming from other progressive revelation in scripture, not an offshoot of logos or philosophy directly. That this Jesus, who was a sacrificial-mediator in history, claimed 'to be God' and 'one with the Father' is probably a better foundation to query the origin of the logos-divinity concept, rather then Philo's, Socrates, or Plato's thoughts. The doctrine of the Divine Son is not really related to Philo or philosophy. The whole word may have had a weak concept of a God and his presence in the world, but only scripture reveals the trinity under any meaningful light.