Counterfactual Computation Critique

Computation is typically defined in terms of counterfactuals – what a system would do with different inputs is an important part of its causal structure. For instance, a conscious algorithm processing input X generates conscious experience not just because of what it actually does on receipt of X, but because it has the capacity to appropriately handle different inputs Y, Z, etc. Consider a simple playback system that just follows a pre-recorded sequence of exactly what the conscious algorithm did when processing input X. This playback produces identical outputs but cannot handle any other inputs – it would fail or break if given input Y. Since it lacks counterfactual sensitivity, it should not be conscious according to computational functionalism.

However, it is possible to construct a hybrid system with a switch that either plays the pre-recorded sequence (if input = X) or runs the full conscious algorithm (if input ≠ X). This hybrid system is counterfactually sensitive because it could handle different inputs, but when actually given input X, only the recording plays while the full algorithm remains completely inert.

This creates a puzzle: we have two systems that do exactly the same thing when processing input X – the simple playback versus the hybrid system. The only difference is unused machinery that makes no causal contribution to the actual processing. Yet according to computational functionalism, one should be conscious (due to counterfactual sensitivity) while the other should not. This conflicts with intuitions that consciousness should depend on causally active processes rather than inert capabilities.