All of these concepts are imprecisely connected to the real world. Does anyone have an idea for how we could more precisely define Gall’s Law to more ably discuss real expected experience?
I’m considering a definition which might include the phrase:
I think the key insight here is that you get a limited number of bits, in design space, to bridge between things that have already been shown to work, and things that have yet to be shown to do so.
For purposes of Gall’s law, we are interested in the number of bits of design that went into the space shuttle without ever having been previously shown to work. So you have to subtract off the complexity of “the idea of an airplane”, which we already had, and of the solid fuel booster rockets, which we already knew how to build; and also of any subassembly which got built and tested successfully in a lab first—but perhaps leaving some bits or fraction of a bit to account for the unknown environment when using them on the real shuttle, versus in the lab.
I think the key insight here is that you get a limited number of bits, in design space, to bridge between things that have already been shown to work, and things that have yet to be shown to do so.
That is a very helpful way to put it: “Gall’s Law” is the claim that there is this limited number of bits.
Of course, put so clearly, it looks kind of trivial, so I think that we should read Gall as further saying that you can get a reasonable intuitive bound on this limit by just looking at the history of innovation, but that people often propose designs when a little reasonable reflection would have shown them that they are proposing to step far beyond this limit.
This is an excellent idea—quantizing bits of design information.
It would also demonstrate that if a designer started at the “space shuttle” level of complexity, and layed out a rough design, that design would probably change drastically as the components were built and tested, and the designer collected more bits of information about how to make the complex system work.
I agree.
All of these concepts are imprecisely connected to the real world. Does anyone have an idea for how we could more precisely define Gall’s Law to more ably discuss real expected experience?
I’m considering a definition which might include the phrase:
“Reducible to previously understood components”
I think the key insight here is that you get a limited number of bits, in design space, to bridge between things that have already been shown to work, and things that have yet to be shown to do so.
For purposes of Gall’s law, we are interested in the number of bits of design that went into the space shuttle without ever having been previously shown to work. So you have to subtract off the complexity of “the idea of an airplane”, which we already had, and of the solid fuel booster rockets, which we already knew how to build; and also of any subassembly which got built and tested successfully in a lab first—but perhaps leaving some bits or fraction of a bit to account for the unknown environment when using them on the real shuttle, versus in the lab.
That is a very helpful way to put it: “Gall’s Law” is the claim that there is this limited number of bits.
Of course, put so clearly, it looks kind of trivial, so I think that we should read Gall as further saying that you can get a reasonable intuitive bound on this limit by just looking at the history of innovation, but that people often propose designs when a little reasonable reflection would have shown them that they are proposing to step far beyond this limit.
This is an excellent idea—quantizing bits of design information.
It would also demonstrate that if a designer started at the “space shuttle” level of complexity, and layed out a rough design, that design would probably change drastically as the components were built and tested, and the designer collected more bits of information about how to make the complex system work.