THE Truth

Pondering the discussion we had in class, i have had some thoughts regarding truth. One thought in particular I keep coming back to is a reflection on CS Lewis's work, "Mere Christianity", in which he speaks of a moral code we all have hardwired in us. It is not something we are taught, but it is something that is just there. This moral code is a standard by which we all judge what is fair, what is right, and what is good. Could this not be considered a singular truth? Sure, it covers a vast multitude of different situations, but it is still a moral code, a singular truth...no? Let me hear your thoughts....especially if you are familiar with Mere Christianity.