Bridgeman (1992) has presented some interesting ideas about the nature of consciousness. I discuss them from a computational point of view, but the concept of consciousness is difficult to grasp, so I will phrase my comments in terms of thought rather than consciousness, since there is at the very least, a strong relationship between the two.
1.1 Bridgeman discusses consciousness in terms of plans and their execution. This fits well with my preference to discuss thought, since the involvement of thought with plans is manifestly obvious. However, although there is planning is obviously relevant, the concept does not seem to capture the full scope of everything we associate with thought or consciousness.
1.2 In equating consciousness with planning Bridgeman has made a bold move yet perhaps it is not bold enough. I would like to suggest that, in the jargon of computer science, thought consists of no more and no less than a simulation. This fits with planning to an extent, for simulation is indeed a useful tool for planning, but simulation need not be as organized as planning, because many different things can be simulated without necessarily being part of a coherent plan.
1.3 Let me make it clear that, as a simulation, thought is no mere abstract computational exercise. It is not just a simulation by the brain, but a simulation involving the body. Thus, emotional states may change during the simulation; muscles may be tensed; saliva may flow during thoughts about food, etc. As part of the simulation, you may react somewhat as you would react to the events if they were real rather than simulated. Thus, some thoughts can lead to intense anger, perhaps even to murderous anger, whereas other thoughts can lead to a sense of calm and relaxation. Roughly speaking, thoughts are a simulation affecting the state of body and mind, and our unconscious recognition ability is used in an evaluative process applied to the resultant states. Language is not a prerequisite for thought, although it certainly enhances it by greatly extending the range of possible simulations.
1.4 We can now relate this to Bridgeman's ideas. In terms of simulation, planning consists of a simulation of some future events or actions. Concentrating on current activities appears to be a simulation of the immediate future. This is almost the same as a simulation of the present and perhaps coincides with Bridgeman's ideas on the carrying out of a plan. But, in addition to simulating the future and present, thought is also used to simulate and review past events. As such it is important to our memory. By reviewing past events through the simulation of thought we provide ourselves with a mechanism for memory reinforcement and indeed it may be through such simulation that we achieve a selective or goal-directed dimension to our learning abilities. Similarly, a simulation of past events is involved in recalling them, so it is an important component of episodic memory. It is perhaps the relationship of simulation to memory that has been most important from the point of view of evolution.
Bridgeman, Bruce (1992) On the Evolution of Consciousness and Language. PSYCOLOQUY 3(15) consciousness.1