John R. Searle () has argued that functional equivalence to a human being, even at the level of the formal structure of neuron firings, is not a sufficient condition for an organism’s having conscious states…To begin this argument we must imagine that we have access to a large pool of homunculi that know a great deal about neurophysiology, and that each homunculus is equipped with a tiny device that can both read the state of a neuron, and change the state of a neuron. Now, one day we talk someone, call him Fred, into undergoing the following series of operations: During the first operation Fred’s skull is opened up and one of his neurons, call it the A neuron, is removed. But right before the neuron is removed, a homunculus is placed in Fred’s skull to take over its functional role. [and so on]
…This paper has, I hope, supported the conclusion that functional equivalence to a human at a very fine level, is a sufficient condition for an organism to have conscious states. It has done this by arguing that the contrary position entails a proposition (ie., (2)) that we have good reason to believe to be false. The fine level of functional organization alluded to, involves reproducing the functional role of each neuron in a normal human brain. Call this circuit functional equivalence.
However functional theories are more attractive, if they do not require as a necessary condition for conscious states, anything as fine grained as circuit functional equivalence. So one thing that would be worth doing would be to show that functional equivalence at some coarser level is sufficient for having conscious states. And I think that this paper can help do this by weakening one’s beliefs to the contrary. (By a coarser level, I mean any level of description X, such that circuit functional equivalence entails equivalence at the X level but equivalence at the X level does not entail circuit functional equivalence.)
To be more specific, consider some of the arguments of Block, Searle and others to the contrary ( and ). In these arguments, creatures are described which are, at some level coarser than the circuit functional, functionally equivalent to a human, but which are, according to these authors, such that they lack conscious states.
However, there seem to be at least two reasons why one might believe that these creatures are not conscious. One reason might be based on the belief that the functional equivalence that the creatures share with a human, is not at the relevant level of organization. The other reason, and I believe the dominant reason, is that one feels at first glance, that they are just not made of the right kind of stuff (eg., they are made of homunculi).
This paper then, should help to weaken intuitions that are based on what the organisms are made of. I say this because I think it has been shown that what is important is not what an organism is made of, but rather functional organization at some level. Hence, if one wishes to maintain that such organisms do not have conscious states, then one is going to have to do this on the grounds that the functional equivalence that they share with a human is not at the relevant level, and not on the grounds that they are not made of the proper material.