Despite the opposition of materialistically orientated scientists, common experience provides overwhelming support for the existence of intentional, self-initiated activity (the nature of intent as its irreducible source will be discussed later). Libet writes:
...that mental processes can influence or control neuronal ones, has been generally unacceptable to many scientists on (often unexpressed) philosophical grounds. Yet, our own feelings of conscious control of at least some of our behavioural actions and mental operations would seem to provide prima facie evidence for such a reverse interaction, unless one assumes that these feelings are illusory. (1994, p.120)
Empirical findings are actually congruent with common sense. Libet's experiments showing that an action can start before the conscious decision to act may be an interesting case. The conclusion is that a decision does not always initiate action, so it is sometimes inferred that action itself triggers neural activity, reducing consciousness to its interpretative or inhibitive role at most. Yet, it is established that a brain module can be activated without corresponding action, which goes against this possibility:
...neural activity (as indicated by measurements of regional blood flow or metabolic rate) has been shown to increase selectively in the supplementary motor area (SMA) when the subject is asked to imagine moving his fingers without actually moving them. (ibid., p.124)
Thus, a more plausible explanation is that a pre-verbal and even pre-thought energy impulse (an intent) initiates an action that is, in turn, faster than formulating the impulse (which is a cognitive process known as decision).
The reason why materialists try to deny intent is not only their affinity for physical determinism but also the fact that the seat of intent cannot be found in the brain. There are modules of the brain that are associated with vision, movement or language, however, these modules are not responsible for intending to move, speak or perceive. Of course, there are some other factors that can activate these brain regions, but it is universal experience that people often move, speak or even perceive because they intend to do so. Yet, no source of intent itself has been located in the cortex. One part of the brain can effect another (e.g. chemicals produced in the amygdala can affect electrical activity in the frontal lobe). However, these are invariably non-intentional effects - any part of the body, including the brain, if left to itself, should operate on the basis of physiochemical laws - it does not have intent. Nor can the source of intent be identified with the whole. This would contradict the principle of causal grounding stating that ‘the causal efficacy of any complex... is entirely dependent upon the causal efficacy of the basic constituents of its physical instantiation' (see Seager, 1995, p.276). To use an example, one part of a car or computer can affect another, but a car or computer as a whole does not affect its constituent parts. Analogously, mental causation cannot be explained by overall activity of the brain. Therefore, if the notion of intent (leading to a self-generated action) is accepted, it makes sense to conclude that it is a property of a non-material component of the human being.
The objection is sometimes raised that non-material intent would break the law of conservation of energy or the first law of thermodynamics (stating that the total energy in a closed system remains constant). But, there are several ways to account for this. The physical world generally and the brain specifically are better perceived as open systems. Any energy gain or loss in one place could easily be stabilised by gains or losses elsewhere, and even if any deviation from the first law existed, it could never be ascertained by measurements. This is especially the case considering that the mass of the deflected electrical current is almost equal to zero so that there is no problem in compensating for a switch which changes the direction of the current in the brain. Furthermore, as Schrödinger states, energy is equal hv, where h is a constant, a v is frequency. So, energy is proportional to the frequency, and frequencies have statistical averages. This is very much relevant for neuronal activity, because the statistical element in the frequencies of the waves would allow for intent without breaking the first law. Even if this is not taken aboard, the low of preservation of energy may not play a role in this case, on the first place. Scott writes:
The Hodgkin-Huxley equations, which describe the dynamics of the nerve impulse on an axonal tree, are not after all, constrained by the conservation of energy. Instead this is a system of nonlinear diffusion equations which - like a lighted candle - balances the rate of electrostatic energy release from the membrane to the power that is consumed by circulating ionic currents. Since the electrodynamics of an individual neuron is not constrained by the First Law of thermodynamics, there is little reason to expect this law to constrain a system at a higher level of organization. (1994, p.156)
- . Willis Harman, who was a distinguished scientist himself, points out that ‘"downward causation", causation-from-consciousness, is for the most part considered unacceptable as a scientific concept in spite of the fact that it is one of the most impressive facts in our practical experience' (1994, p. 141).