James Culbertson’s claim that one could, in principle, build robots from flip‑flops that reproduce a… — Hubert L. Dreyfus

James Culbertson’s claim that one could, in principle, build robots from flip‑flops that reproduce any human behavior by meeting arbitrary input‑output specifications simply assumes, without evidence, that human inputs and outputs can be isolated and correlated like digital signals, an assumption undermined by neurophysiological considerations.

By Hubert L. Dreyfus, from What Computers Can't Do

Key Arguments

Dreyfus cites Culbertson’s construction argument: 'Using suitable receptors and effectors we can connect them together via central cells. If we could get enough central cells and if they were small enough and if each cell had enough endbulbs and if we could put enough bulbs at each synapse and if we had time enough to assemble them, then we could construct robots to satisfy any given input-output specification, i.e., we could construct robots that would behave in any way we desired under any environmental circumstances.'
Culbertson then draws the strong conclusion: 'There would be no difficulty in constructing a robot with behavioral properties just like John Jones or Henry Smith or in constructing a robot with any desired behavioral improvements over Jones and Smith.' and more baldly, 'Since [these complete robots] can, in principle, satisfy any given input-output specifications, they can do any prescribed things under any prescribed circumstancesingeniously solve problems, compose symphonies, create works of art and literature and engineering, and pursue any goals.'
Dreyfus objects that 'as we have seen in Chapter 4, it is not clear in the case of human beings what these inputs and outputs are supposed to be.11*'
He notes that 'Culbertson's assumption that the brain can be understood as correlating isolated bits of data rests on the assumption that the neurons act as on/off switches. Since, as we have seen in Chapter 3, this is probably not the case, there is no reason to suppose, and several reasons to doubt, that human inputs and outputs can be isolated and their correlation formalized.'
He concludes, 'Culbertson's assumption is an assumption and nothing more, and so in no way justifies his conclusions.'

Source Quotes

Using suitable receptors and effectors we can connect them together via central cells. If we could get enough central cells and if they were small enough and if each cell had enough endbulbs and if we could put enough bulbs at each synapse and if we had time enough to assemble them, then we could construct robots to satisfy any given input-output specification, i.e., we could construct robots that would behave in any way we desired under any environmental circumstances. There would be no difficulty in constructing a robot with behavioral properties just like John Jones or Henry Smith or in constructing a robot with any desired behavioral improvements over Jones and Smith.

If we could get enough central cells and if they were small enough and if each cell had enough endbulbs and if we could put enough bulbs at each synapse and if we had time enough to assemble them, then we could construct robots to satisfy any given input-output specification, i.e., we could construct robots that would behave in any way we desired under any environmental circumstances. There would be no difficulty in constructing a robot with behavioral properties just like John Jones or Henry Smith or in constructing a robot with any desired behavioral improvements over Jones and Smith. 9 Or put more baldly: Since [these complete robots] can, in principle, satisfy any given input-output specifications, they can do any prescribed things under any prescribed circumstancesingeniously solve problems, compose symphonies, create works of art and literature and engineering, and pursue any goals.

There would be no difficulty in constructing a robot with behavioral properties just like John Jones or Henry Smith or in constructing a robot with any desired behavioral improvements over Jones and Smith. 9 Or put more baldly: Since [these complete robots] can, in principle, satisfy any given input-output specifications, they can do any prescribed things under any prescribed circumstancesingeniously solve problems, compose symphonies, create works of art and literature and engineering, and pursue any goals. 10 But as we have seen in Chapter 4, it is not clear in the case of human beings what these inputs and outputs are supposed to be.11* Culbertson's assumption that the brain can be understood as correlating isolated bits of data rests on the assumption that the neurons act as on/off switches.

9 Or put more baldly: Since [these complete robots] can, in principle, satisfy any given input-output specifications, they can do any prescribed things under any prescribed circumstancesingeniously solve problems, compose symphonies, create works of art and literature and engineering, and pursue any goals. 10 But as we have seen in Chapter 4, it is not clear in the case of human beings what these inputs and outputs are supposed to be.11* Culbertson's assumption that the brain can be understood as correlating isolated bits of data rests on the assumption that the neurons act as on/off switches. Since, as we have seen in Chapter 3, this is probably not the case, there is no reason to suppose, and several reasons to doubt, that human inputs and outputs can be isolated and their correlation formalized.

Since, as we have seen in Chapter 3, this is probably not the case, there is no reason to suppose, and several reasons to doubt, that human inputs and outputs can be isolated and their correlation formalized. Culbertson's assumption is an assumption and nothing more, and so in no way justifies his conclusions. The committed formalist, however, has one more move.

Key Concepts

we could construct robots to satisfy any given input-output specification, i.e., we could construct robots that would behave in any way we desired under any environmental circumstances.
There would be no difficulty in constructing a robot with behavioral properties just like John Jones or Henry Smith
Since [these complete robots] can, in principle, satisfy any given input-output specifications, they can do any prescribed things under any prescribed circumstancesingeniously solve problems, compose symphonies, create works of art and literature and engineering, and pursue any goals.
it is not clear in the case of human beings what these inputs and outputs are supposed to be.
Culbertson's assumption is an assumption and nothing more, and so in no way justifies his conclusions.

Context

Within Dreyfus’s critique of the argument from complete input‑output specification to human‑level robots, used as an example of unjustified extrapolation from switch‑based hardware to human behavior.