The Torah begins with a Bet for many many different reasons. .... The numerical value of 2 ....
Indeed, without "duality" life could not exist.
I once asked my teacher why some of the Sethites and some of the Cainites had so similar names.
It led me and him to undertake a study on what we, as a working title or for simplicity's sake, ended up just referring to as "Biblical Duality" or "Biblical Polarities".
Connected to the concept of polarities is the concept of the obscuration of truth.
I learned many years ago that the word Olam, world, is derived from or connected to Alam, to hide.
So for the world to even exist, the truth has to be hidden in some way, there needs to be some kind of obscuration of the truth (Prov. 25:2), or it's light would just be the only thing to exist, and there wouldn't be anything for the light to illuminate or interact with. Actually the truth can possibly be stated outright, in full, but there has to be at least some "ambiguity" involved. Hence every Hebrew word can mean at least two things.
There must be 2 genders, 2 poles, a positive and negative charge, etc. etc.
Daniel talks about people being refined like powder. For that to happen, the substance being refined must be between a mortar and a pestle, in other words, must be worked on from two directions.
2 may be the number of physical existence, but 4 seems to be the number of physical space.
2 when doubled is 4. Vertical and horizontal are two things, which when added together make four directions. The many correlations of the number 4 mostly gain significance from being in turn correlated to the four Chayyot and their four faces, and the four directional divisions of the tribes in the Sinai wandering.