It is obvious that the Torah and definitely the rest of the Tanach, was written by a number of people. In fact, it is very likely that it was only canonised in the time of Ezra, the Scribe. However, the tradition states that the Torah was given by God, and written by Moses.
- Written by the finger of G-d (on special tablets)
- Written by Moses on stone tablets
- Written by various authors, till canonised.
Let us unpack this a bit. Firstly, the tablets written by G-d, were destroyed by Moses. They were special, and could be read by any one of the 70 languages in the world at the time.
Then, what did Moses write on those tablets. The 10 commandments? Which version? Did he write them in brief, i.e., Do not kill, as is illustrated? What more could he have fitted on two stone tablets that he could carry down the mountain, and that could fit into the Ark of the Covenant.
One could even ask what is it that G-d transmitted to the people (or Moses)? With what voice? G-d can only speak to us through facilities that we have. In other words, if it says G-d spoke, either He used the “voice” of someone, or He transmitted it in dreams, or in “imaginary” visions. These are all facilities we posses – the last of which people in general, are very leery of.
We know that is because there is a consensual reality that we all agree upon, and not a spiritual reality that we are willing to settle upon. Thus, we can ascertain the “truth” of something that has manifested in our reality, but cannot evaluate what is truly going on in someone’s mind. We have no valid and agreed upon way of ascertaining whether someone is really in connection with that inner or other reality or not. Nor can we evaluate the authenticity of the information he delivers from the “unseen” realms of existence.
Therefore, if G-d wanted (or needed) to transmit some information to us, He would use one (or more) of us to do so. That the Torah was written by more hands than Moses, and the rest as well, does not mean that it was not written “by the Hand of G-d” using human’s to do so. It is just written by people who are G-d inspired. This is what is believed of the writers of the Gospels, which forms the basis of the Christian faith.