Here is an excerpt from an article titled
Biological Perspectives in Criminality. Although the article is focused on crime, I find its analysis of biology and personal freedom quite relevant to human life in general:
The acceptance of biological explanations for human behavior has been thought by many to preclude the possibility of free will. This fundamental fear has resulted in a pervasive rejection of biological contributions to behavior. Although some behavioral scientists are deterministic in their views, attributing behavior to everything from socioeconomic conditions to neurochemical events, most individuals prefer to credit their own free will for their behavior. A compromise reflecting a more accurate position on the forces behind human behavior is widely accepted, however--the theory of "conditional free will" (see Denno, 1988, for discussion of "degree determinism," a related view).
In probabilistic or stochastic theories, numerous causes or alternatives are presented to explain an effect. Each cause has a certain probability of resulting in that outcome, in some cases a measurable probability. Because it is rarely the case that an effect can be associated with only one cause, some dynamic interaction of causes, working in concert, is frequently responsible for the final result. In the assessment of human behavior, a most complex phenomenon, it is particularly difficult to separate those causes to assess their relative contributions.
In accordance with probability theory, social human behavior is contingent on a countless number of possible decisions from among which the individual may choose. Not all of those decisions are feasible, however, nor are the resources available that are required to act on them. Choosing a course of action, therefore, is limited by preset boundaries, which narrows the range of possibilities substantially. Decision‑limiting factors include current circumstances and opportunities, learning experiences, physiological abilities, and genetic predispositions. Each one of these conditions collaborates internally (physically) and externally (environmentally) to produce a final action. The behavioral result is thus restricted to options available within these guidelines, yet it is "indeterminable" and cannot be precisely predicted. Stable individuals generally behave with some degree of expectability, however. In other words, certain patterns of behavior are a common individual characteristic, and some patterns are more probable than others in a given situation in a given individual.
The principle of conditional free will does not demand a deterministic view of human behavior. Rather, it postulates that individuals choose a course of action within a preset, yet to some degree changeable, range of possibilities and that, assuming the conditions are suitable for rational thought, we are accountable for our actions. Given "rational" thought processes, calculation of risks versus the benefits, and the ability to judge the realities that exist, the result is likely to be an adaptive response, that is, the behavior will be beneficial for the individual and the surrounding environment.
This theory of conditional free will predicts that if one or more conditions to which the individual is exposed are disturbed or irregular, the individual is more likely to choose a disturbed or irregular course of action. Thus, the risk of such a response increases as a function of the number of deleterious conditions. For example, a child with a learning disability may function well in society. With the addition of family instability, lack of appropriate educational programs, and a delinquent peer group, however, the learning‑disabled child may be more prone to maladaptive behavior, which may, in turn, result in actions society has defined as criminal. The child's range of possible decisions has, in other words, been altered.
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This is quite close to my own philosophy on the matter. Where you are right now determines where you can go, what immediate paths you can take -- but the direction in which you go is up to you. If you on a mountain, you can climb down into the valley or follow the path over to the next hill. The fact that you cannot jump instantaneously to the other side of the globe (well, not with our current technology) is not a negation of free will, but simply a relative limitation of it.
This also raises interesting issues about personal responsibility. There is one extreme, sometimes called "blaming the victim" (New Agers like me are often accused of that), which involves giving a person full responsibility for bad consequences and outcomes even if he genuinely did not know of any better alternatives, and, in his then-current situation, had no way of finding any. (For instance: People in NOLA did not get out in time, although they presumably could have; therefore it is their own fault that they drowned.) On the other extreme, people are excused completely from responsibility due to whatever effects of heredity and environment supposedly "compelled" them to make the choices they did.
I think the middle position makes the most sense. One cannot evaluate someone's choices without knowing what they had to choose from -- not only externally, but internally. A person who lacks the IQ, knowledge, education or imagination to generate different possibilities, does, in fact, have less freedom of choice than a person with greater cognitive ability, even in identical external circumstances. We are only as free as we can imagine ourselves being. That is why I regard the enhancement of human consciousness as a necessary tool for freedom.