Sorry if this questions sounds trivila for the dopers experienced in the military, but I don’t really know a lot about how military herarchies work. My question is: Is any soldier obliged to obey orders from any soldier of superior rank? I mean, would for example a Captain who is on duty be obliged to obey orders from a Major he happens to meet while on service, or would it be necessary that this Major is superior to him in the chain of command of the unit he serves in?
I guess it’s the latter, but then I wonder why we need those detailed hierarchies of ranks if it’s not the rank that really counts, but the position as leader of a particular unit.
Related question: A read a bit about military ranks and organizations, and it seems that the commanders of units of similar size are usually headed by officers of similar ranks (for example, as I read in Wikipedia, a battalion in the US Army is typically commanded by a Lieutenant Colonel). It seems to me that the number of levels of military units (platoons, companies, battalions, divisions, whatever) is smaller than the number of ranks there are. Does, for example, a Private First Class have any priority or authority over an ordinary Private if they serve in the same unit, of which someone else is commander?