> There is literally no way for the pedal to know if it succeeded or not. Success for the pedal is defined in terms of what it can know, same as any other comp

> There is literally no way for the pedal to know if it succeeded or not. Success for the pedal is defined in terms of what it can know, same as any other component in a system. The pedal is typically a mechanical device, so what it can know is restricted to its mechanical outcomes. Was the floor mat stuck behind it? If so, pressing the thing to 100% only results in an outcome of 50% depression -- maybe that's failure. And so on. It's incoherent for depress_accelerator to return information about the car in which the engine it is connected to is installed. Does `ls /mnt/volume/file` return information about the chassis of the server in which the hard drive hosting `/mnt/volume` is installed? > it doesn't make sense to think of [programs/systems] only in terms of a single "main." Why not? You can absolutely model any program, composed of arbitrarily many parts/components, as a graph of components with a single root. I acknowledge that's not the only model, but it's definitely universal and effective. > In particular, side channels of information are setup to route some errors/information back to a user that are not necessarily part of any individual function. And some systems should panic/fail instead of trying to continue, given the state of the system. What do you mean by "errors/information ... not part of any individual function"? Isn't it the case that anything which could produce an error is necessarily part of a function i.e. a sub-tree of the execution call stack? If I write a fn doSomething(input x), why should the result of my implementation do anything, in general, other than return execution to my caller with an appropriate result value? > So, if something is being punted up from inside a software system, it makes sense to have an exception be there, to me. As it does, as well, to the article in this post. I can think this, all the while also agreeing that most of the time using return based responses makes a lot of sense. Functions define layers of abstraction. A given function knows only its own implementation, narrow properties of its caller (input parameters and output expectations), and the characteristics of the functions it calls as defined by the signatures of those called functions. There should never be the concept of something "being punted up from inside a software system". A function is defined in terms of its inputs and outputs. Its success or failure is defined in terms of those things only.