Board Thread:Assassin's Creed general discussion/@comment-26314858-20150714112803/@comment-18014300-20170516014808
According to Assassin's Creed: The New Essential Guide, it is "unclear" whether the Father of Understanding actually refers to a deity or not. The phrase, often invoked in greetings and ritual ceremonies, is meant to symbolize the "sense of order and logic" the Templars embrace.
I personally think that the Templars are not actually really that logical especially since the Assassins are the ones whose Creed actually says that to be wise, one has to know that one knows nothing, and therefore search truth through empirical reasoning while recognizing that no truth is absolute because our understanding of it is limited by our observations and interpretations. The Templars do not have this prescription, often believing that they are the wisest among humanity (therefore entitled to shepherd them), or that they are so intelligent that they have arrived at Truth almost intuitively. I think therefore underlying the Father of Understanding is something almost religious or superstitious, though not quite, in that it almost seems to represent how their notion that they possess wisdom, Truth, and logic is zealous and presumptuous, like a faith in and of itself. The Assassins contrast because their epistemological views rejects faith that one has truly acquired the Truth.
It is less significant whether Templars regard the "Father of Understanding" as an actual deity or not; the importance lies in what it symbolizes: their mindset that their ideology is so righteous and unquestionable, that they almost act as though it is divinely guided. Whether or not they truly believe the Father is a deity or not, they appeal to this character, this motif, because it embodies their mentality of seeing Truth as something that can be understood by just "knowing", intuitively, not so unlike religious people, even though they say they belief in "logic", their faith in how indisputable their "logic" is is almost a religion in and of itself.