Also, any explanation is necessarily non-linear (you cannot go from one concept... to another... directly to conclusion... because the universe can only to be explained in the context of a hierarchical structure). Hence, one explains down to an arbitrary level then returns and explains down another branch of the structure. On the way, there are many sidetracks which require the exercise of judgement in regard to which path to follow, when to follow it and for what distance.
A theory without numbers is as worthless as numbers without a theory. Wherever possible then, a calculation is made to show that theory is reasonably in line with quantitive observations (which I accept as the only proper falsifiers).
This analysis is based entirely on reductionist philosophy (understanding by dismantling into component parts). I regard any other form of understanding as non-rational.
The words quantitative and qualitative are rendered as quantitive and qualitive as a matter of personal preference.