All one need do is ask how plausible it is to maintain that every time a person purposefully chooses to do something such as move his fingers to type, an initial neuron just happens to fire at random (as a result of quantum fluctuations, etc.) with the result that finger movements occur that perfectly mesh with or map onto those that are intended by that person. Because such repeated coincidences would literally be, dare we say, miraculous, the only plausible view is that the neuron must not be firing randomly but because of the causal input from a person choosing to act for a purpose.
One of the things [Wilder Penfield] noticed in his experimental work was that his patients reported being consciously aware of the distinction between being agents and doing things, and being patients and having things done to them. Phenomena such as this led him to endorse dualism....One can surmise, then, that had Penfield been presented with the argument from causal closure, he would have found it wanting. And for good reason. In seeking to understand how events of different physical entities affect the capacities of micro-entities such as neurons, a neuroscientist such as Penfield is seeking to learn about properties of physical entities that are essentially conditional or min nature. A property that is conditional in nature is one specified in terms such as "If such and such is done to object 0 (e.g., a cause C is exerted on 0), then so-and-so will occur to 0 (e.g., 0 will move at rate R)." As the Nobel physicist Richard Feynman says, scientific questions are "questions that you can put this way: `if I do this, what will happen?'... And so the question `If I do it what will happen?' is a typically scientific question" (Feynman 1998, 16, 45). Chalmers's description of basic particles that are studied by physicists nicely captures their iffy nature: "Basic particles ... are largely characterized in terms of their propensity to interact with other particles. Their mass and charge is specified, to be sure, but all that a specification of mass ultimately comes to is a propensity to be accelerated in certain ways [moved at certain rates] by forces, and so on.... Reference to the proton is fixed as the thing that causes interactions of a certain kind that combines in certain ways with other entities, and so on" (Chalmers 1996, 153).
What Chalmers describes as a propensity of a particle to be accelerated is a capacity of it such that if it is actualized by an exercised power of another entity (whether physical or nonphysical in nature), the particle will be necessitated to accelerate. There is nothing, however, in the nature of the propensity or capacity of that particle that requires that it be actualized only by purposeless causal events of physical entities so that the physical world is closed to causal influence of mental events of souls choosing and intending to act for reasons. Hence, the actualization of a microparticle's capacity by a mental event on an occasion when a person chooses to act for a reason is not excluded by anything that is discovered in a scientific study of that capacity. And it is precisely on occasions like those involving the movements of our fingers and arms while typing that a neuroscientist will reasonably believe that the microphysical neural impulses that led to those finger movements must ultimately have originated with the mental causal activity of a soul that was choosing to act for a purpose. If a neuroscientist makes the presupposition that microphysical entities can have their capacities actualized only by other physical entities and never by choices made by souls for purposes, then he does so as a strict naturalist and not as a scientist.
The problem is that according to strict naturalism, a scientific examination of the causes of bodily action leaves no explanatory room for anything nonphysical. Scientific explanations must by their very nature be limited to physics, chemistry, and biology. The philosopher Jaegwon Kim argues that a neuroscientist (indeed, any scientist) has a methodological commitment to the causal closure of the physical world.
If we make libertarian choices that are explained teleologically and carry them out, then there must be irreducible mental-to-physical causation. (By "mental" we simply mean any psychological state or activity such as believing, intending, desiring, and so on.)
By way of summary, a teleological explanation of a choice to perform an action involves an agent (i) having a belief or a desire in the content of which he conceives of or represents the future as including a good state of affairs that is an end or goal to be brought about or produced; (2) conceiving of or representing in the content of a belief the means to the realization or bringing about of this end, where the means begin with the agent performing an action; and (3) making a choice to perform that action in order to bring about the end.
A choice is an undetermined mental action, and when we make choices we typically explain our making them in terms of reasons, where a reason is a purpose, end, or goal for choosing. A reason is a conceptual entity, what medieval thinkers called an ens rationis (literally "object of reason") or intentional object, which is about or directed at the future and optative in mood (expressing a wish that the world be a certain way that is good). To put this point in technical terms, while a reason is not a desire or a belief, its optative character stems from its being grounded in the content of a desire or belief that represents a future state of affairs as good and something to be brought about by a more temporally proximate chosen action of the person who has the desire or belief. An explanation of a choice in terms of a reason or purpose is a teleological explanation.
A study of the literature about strict naturalism, however, leads one to believe that in the end strict naturalists appeal to one central argument in support of their view - "the argument from causal closure:"
One argument against strict naturalism would be to maintain that the view is self-defeating: its proponents believe that it is true and seek to convince us of its truth, whereas if the view is true, then there ultimately is no such thing as believing that it is true because there ultimately are no psychological events of any kind, period.
Strict naturalism contests the truth of the natural understanding of ourselves. It maintains that there are no ultimate and irreducible purposeful explanations of events, that there is no libertarian free will, and that there are no irreducible psychological or mental properties and events.
The idea that subjective experience may be either eliminated or fully incorporated in an exclusively scientific understanding of the world is espoused by virtually every strict naturalist.
Sometimes the rejection of dualism is couched in terms of the rejection of an enduring, substantial self that remains self-identical through time. For example, Dennett advocates a strict form of naturalism that entails that we, qua minds, are not substantial selves but systems of organized parts.
Strict naturalism is incompatible with libertarian freedom because undetermined free choices are choices that are ultimately explained by the purposes of the agents who make them. Hence, because strict naturalism excludes ultimate teleological explanations in terms of purposes, it excludes libertarian free will.
The goal of strict naturalism is to take the beliefs, desires, preferences, choices, and so on that appear to make up our conscious, intelligent, psychological life and explain them in terms that are nonconscious, nonmental, and nonpsychological.
If strict naturalism is true, then there is no ultimate and irreducible teleological explanation of any event, let alone our actions, in terms of a purpose; there is no libertarian freedom of the will; there are no irreducible experiences of pleasure and pain; there is no enduring self or soul of any kind; and God, if God exists, is explanatorily irrelevant to events that occur in our world.
Naturalism - very roughly - maybe defined as the philosophy that everything that exists is apart of nature and that there is no reality beyond or outside of nature.
