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Determinism and Free Will in Science and Philosophy

1 The Doctrine of Determinism

Determinism is a far-reaching term affecting many areas of concern, that most widely and radically states that all events in the world are the result of some previous event, or events. In this view, all of reality is already in a sense pre-determined or pre-existent and, therefore, nothing new can come into existence. This closed view of the universe and of our world holds all events to be simply the effects of other prior effects. This has radical and far-reaching implications for morality, science, and religion. If general, radical, determinism is correct, then all events in the future are unalterable, as are all events in the past. A major consequence of this is that human freedom is simply an illusion.

2 Genetic Determinism

One area of contemporary discourse in science that relates to the issue of human freedom is the notion of genetic determinism. Here, the concept of determinism is linked directly to the genes in the DNA of a person. Because we already know that aberrations in certain genes can lead to various forms of physical and mental disease in humans, we can say with some certainty that people are physically determined by their genes. But genetic determinists want to extend this further, by claiming that even our behaviour is determined by our genes. In this line of thinking, we are but victims of our genetic makeup, and any effort to change our moral nature or behavioural patterns is useless. This is sometimes termed "puppet determinism," meaning metaphorically that we dance on the strings of our genes.

There are two principle forms of genetic determinism; Genetic Fixity and Innate Capacity. Together they link-up to produce the doctrine of statistical variation. These are discussed below.

a) Genetic Fixity: Sphexishness

The first variety of genetic determinism is the rather unsophisticated doctrine of genetic fixity, which holds that the genes of parents inevitably determine the characteristics of their children. Dan Dennett [1996] encapsulates this simple form of determinism under the label SPHEXISHNESS from the powerful example of the digger wasp, Sphex ichneumoneus:

"When the time comes for egg laying, the wasp Sphex builds a burrow for the purpose and seeks out a cricket which she stings in such a way as to paralyze but not kill it. She drags the cricket into the burrow, lays her eggs alongside, closes the burrow, then flies away, never to return. In due course, the eggs hatch and the wasp grubs feed off the paralyzed cricket, which has not decayed, having been kept in the wasp equivalent of deep freeze. To the human mind, such an elaborately organized and seemingly purposeful routine conveys a convincing flavor of logic and thoughtfulness--until more details are examined. For example, the Wasp's routine is to bring the paralyzed cricket to the burrow, leave it on the threshold, go inside to see that all is well, emerge, and then drag the cricket in. If the cricket is moved a few inches away while the wasp is inside making her preliminary inspection, the wasp, on emerging from the burrow, will bring the cricket back to the threshold, but not ins ide, and will then repeat the preparatory procedure of entering the burrow to see that everything is all right. If again the cricket is removed a few inches while the wasp is inside, once again she will move the cricket up to the threshold and re-enter the burrow for a final check. The wasp never thinks of pulling the cricket straight in. On one occasion this procedure was repeated forty times, always with the same result."
- D. Woodridge, 1963, p. 82.

Dennett (1996), following Hofstadter (1982), calls this kind of very simply determined behaviour ‘sphexish’, but believes that too much has been made of emblematic stories (or intuition pumps) like the one above, because human behaviour is much more complexly determined.

Genes, of course, do influence human development. The differences between humans and chimps are almost entirely genetic. However, even the completion of the human genome project will not enable scientists to predict how a child will develop. Indeed, even a complete knowledge of a child's genes and developmental environment would not allow the complete specification of the organism: chance also plays a significant role in development. This can be seen, for example, in the number of bristles under a fruit fly's wing: this number varies from the left wing to the right, despite the fact that the fruit fly has the same genes and environment on both sides of its body (Lewontin, 1991). Such differences may not be due to pure chance, however, but rather to non-linear dynamic (chaotic) deterministic processes (Molenaar, Boomsma, & Dolan, 1993). Such processes have been shown possible using computer simulations, but whether they operate in real organisms remains an empirical question.

b) Innate Capacity

The second variety of genetic determinism is the slightly more sophisticated doctrine of innate capacity, according to which people are like buckets waiting to be filled (Lewontin, 1991). In an impoverished environment, all people will end up with similar characteristics (wealth, knowledge, etc.); but in an enriched environment, those who naturally have big buckets will end up with more than those with small buckets could possibly hold. For example, people who are malnourished will show smaller individual differences in height than those who are well nourished.

The Doctrine of Statistical Variation

Genetic fixity and innate capacity lead the genetic determinist to the doctrine of statistical variation. This doctrine states that all individual differences can be parsed into either genetic determinants or environmental determinants in some proportion (Lewontin, 1991). For example, it might be said that 80 percent of the variance in children's performance on I.Q. tests is due to genetic influences, and only 20 percent is due to environment. The practical implication seems to be that even a radical change in environment will have only a modest effect on performance. However, this is not the case, as can be seen from the following examples:

i) An ordinary student in primary school today can add a column of numbers much faster than even the most intelligent ancient Roman mathematician, who had to deal with cumbersome X's, V's, and I's. Further, the same student, using an inexpensive calculator, can multiply two five-digit numbers faster than even the most intelligent mathematician a century ago (Lewontin, 1991).

ii) Heritability does not imply immutability. This can be seen from the example of PKU (phenylketonuria), a form of retardation. PKU can be cured by stopping people from eating phenylalanine. One hundred years ago the proportion of genetic variation in acquiring PKU was 100 percent; now individual differences in acquiring PKU are almost completely non-genetic (Plomin, DeFries, & McClern, 1990).

Further Considerations

Genetic determinism gains additional support and wider influence from the popular notion that, since we can now establish a scientific connection between one's genes and one's actual and/or potential physical traits (hair and eye colour, disease susceptibility, etc), then we should use this knowledge to restructure the genetic make-up of certain individuals. In other words, genetic determinism does not just show us how we are victims of our genes; it also shows us how we can use the knowledge of our genes in order to change them and, therefore, change ourselves. This understanding of GENETICS and human freedom, or unfreedom as it were, illustrates the extent to which genetic determinists place the influence of nature (biology and genetics) over nurture (society and family). The fundamental premises of genetic determinism, therefore, come to be that:

  • We are victims of our genes and have no ultimate freedom, and
  • With proper knowledge, we can take charge of our genes so that we are no longer their victim, but rather, are their architect. This premise has been termed "Promethean determinism," meaning that with the proper knowledge we can take charge of our genetic and, therefore, moral/ behavioural makeup.

Though a fascinating and long-debated theory, determinism raises serious difficulties regarding the nature of human knowledge and its bearing on our understanding of morality. For example, if one adheres to the idea of determinism and believes that one's life is simply the mechanical and unchangeable outplay of forces beyond one's control, then how does this affect one's relationship to the world and other people. Further questions arise: Does adherence to determinism not lead one into a sense of meaninglessness and impotence regarding one's fate and actions? Does determinism not also lead one into the belief that whatever one does is morally acceptable, by virtue of the fact that whatever one does is already pre-determined, and therefore, meant to be?

If determinism is in fact true, then our whole conception of morality is a pointless illusion. Since everything in existence is the result of necessary and pre-determined causes, then even something like murder can be considered normal. Here, determinism fails to take into account human freedom and choice. The majority of humans would choose not to be killed, just as most humans would choose not to kill another human. Determinists can claim that our choice to be killed or not to kill is itself already a determined effect, but this is only of theoretical interest since the issue of one's life or death is of extreme existential significance. In other words, in relation to issues of morality, determinism is an interesting theory, but in practice it is quite untenable. In essence, the acceptance of determinism makes one into a mere thing, a mechanical and non-autonomous entity without the power to deliberate or change one's direction in life.

3 Free Will

The alternatives to determinism are non-deteminsm, freedom or free will. Here we shall focus on the notion of free will, the doctrine that we as conscious human beings are free to make genuinely undetermined choices in circumstances where we are genuinely able to do so, and where we so freely, or (relavently) unconstrainedly, choose to do so.

Like determinism, free will comes in a variety of types and strengths. Here we shall consider the general scientific view of free will and two common types of philosophical approach to this notion.

3a Free Will: The Scientific View

There is a general scientific picture of the world that lends itself to predictability and certainty of outcomes and hence more to determinism than any notions of freedom or free will. Indeed in many minds, science is still associated with the deterministic picture of the world, as it was in the nineteenth century. Modern science, however, draws a picture that is quite different.

The world according to nineteenth century science was, broadly, as follows. Very small particles of matter move about in virtually empty three-dimensional space. These particles act on one another with forces that are uniquely determined by their positioning and velocities. The forces of interaction, in their turn, uniquely determine, in accordance with Newton's laws, the subsequent movement of particles. Thus each subsequent state of the world is determined, in a unique way, by its preceding state. Determinism was an intrinsic feature of the scientific WORLDVIEW of that time. In such a world there was no room for freedom: it was illusory. Human beings, themselves merely aggregates of particles, had as much freedom as wound-up watch mechanisms.

In the twentieth century the scientific worldview underwent a radical change. It has turned out that subatomic physics cannot be understood within the framework of the Naive Realism of the preceding scientists. The Theory of Relativity and, especially, Quantum Mechanics require that our worldview be based on a critical (scientific) philosophy, according to which all our theories and mental pictures of the world are only devices to organise and foresee our experience, and not the images of the world as it "really" is. Thus along with the twentieth-century's specific discoveries in the physics of the micro-world, we should consider the emergence of a properly critical philosophy as a scientific discovery, and as one of the greatest scientific discoveries of the twentieth century.

We now know the notion that ‘the world is "really" space in which small particles move along definite trajectories’, is illusory: it is contradicted by experimental facts. We also know that determinism, i.e. the notion that in the last analysis all the events in the world must have specific causes, is illusory too. On the contrary, freedom, which was banned from the science of the nineteenth century as an illusion, became a part, if not the essence, of reality. The mechanistic worldview saw the laws of nature as something that uniquely prescribes how events should develop, with indeterminacy resulting only from our lack of knowledge; contemporary science regards the laws of nature as only restrictions imposed on a basically non-deterministic world. It is not an accident that the most general laws of nature are conservation laws, which do not prescribe how things must be, but only put certain restrictions or constraints upon them.

There is genuine freedom in the world. When we observe it from the outside, it takes the form of quantum-mechanical unpredictability; when we observe it from within, we call it our free will. We know that the reason why our behaviour is unpredictable from the outside is that we have ultimate freedom of choice. This freedom is the very essence of our personalities, the treasure of our lives. It is given us as the first element of the world we come into.

Logically, the concept of free will is primary, impossible to derive or to explain from anything else. The concept of necessity, including the concept of a natural law, is a derivative: we call necessary, or predetermined, those things which cannot be changed at will, or by will.

3b Free Will: The Philosophical View

Most people, if asked, would like genuine freedom of choice, proper free will, but can we really have it? Philosophy offers a more complex analysis of this issue than the general scientific view outlined above. Within the philosophical tradition, and given the general set of philosophical principles belonging to this tradition, there are two main strands of argument for free will, i) ethical and, ii) psychological. It is the set of psychological considerations that concern us more directly here, though, of course the ethical concerns are always present in the background to any debate.

As the main features of the doctrine of free will have been sketched in the history of the problem, a very brief account of the argument for moral freedom will now suffice. Will, where viewed as a free power, is defined by defenders of free will as the capacity of self-determination. By self is here understood not a single present mental state (William James), nor a series of mental states (David Hume and JS Mill), but an abiding rational being which is the subject and cause of these states. We should distinguish between:

  • Spontaneous acts, those proceeding from an internal principle (e.g. the growth of plants and impulsive movements of animals);
  • Voluntary acts in a wide sense, those proceeding from an internal principle with apprehension of an end (e.g. all conscious desires); and, finally
  • Those voluntary in the strict sense, that is, deliberate or free acts.

What distinguishes a voluntary act from a non-voluntary one is that there is a self-conscious advertence (to turn one’s attention to) to our own causality or an awareness that we are choosing the act, or acquiescing in the desire of it.

Spontaneous acts and desires are opposed to coaction or external compulsion, but they are not thereby morally free acts. They may still be the necessary outcome of the nature of the agent as, e.g. the actions of lower animals, of the insane, of young children, and many impulsive acts of mature life. The essential feature of free volition is the element of choice - the vis electiva, as St. Thomas Aquinas calls it, or ‘because we want to’ as Billie Piper puts it. There is a concomitant interrogative awareness in the form of the query "Shall I acquiesce or shall I resist?", "Shall I do it or shall I do something else?", and the consequent acceptance or refusal, ratification or rejection, though either may be of varying degrees of completeness. It is this act of consent or approval, which converts a mere involuntary impulse or desire into a free volition and makes me accountable for it.

A train of thought or volition deliberately initiated or acquiesced in, but afterward continued merely spontaneously, without reflective advertence to our elective adoption of it, remains free in causa (for there was a choice, a free choice, about bringing it about). I am therefore responsible for it, though actually the process has passed into the department of merely spontaneous or automatic activity. A large part of the operation of carrying out a resolution, once the decision is made, is commonly of this kind.

The question of free will may now be stated thus. "Given all the conditions requisite for eliciting an act of will except the act itself, does the act necessarily follow?" Or, "Are all my volitions the inevitable outcome of my character and the motives acting on me at the time?" Fatalists, necessarians, and determinists answer "Yes" to this question. Libertarians, indeterminists and anti-determinists reply "No" to it. The mind or soul in deliberate actions is a free cause. Given all of the conditions requisite for action, we (in virtue or our mind or soul) can either act or abstain from action. It can, and sometimes does, exercise its own causality against the weight of character and present motives.

Ethics and Psychology in Free Will

The evidence for the existence of genuine free will usually consists of one of two kinds, the ethical and the psychological, though the psychological arguments often appeal to ethical considerations, and even the ethical arguments themselves are, in some sense, psychological.

i) Ethical Arguments for Free Will

Necessarianism, fatalism or determinism in any form are usually held to be in conflict with the chief moral notions and convictions of mankind at large. The actual universality of such moral ideas is indisputable. Duty, moral obligation, responsibility, merit, and justice signify notions universally present in the consciousness of normally developed human beings. Further, these notions, as universally understood, imply that human beings really are the master of some of their acts, that they are, at least at times, capable of self-determination, that all their volitions are not the inevitable outcome of their circumstances. This implies that when I say that I ought not to have performed some forbidden act, that it was my duty to obey the law, I imply that I could have done so. The judgement of all human beings is the same on this point. When we say that a person is held justly responsible for a crime, or that they deserve praise or reward for an heroic act of self-sacrifice, we mean th at they were the author and cause of that act in such fashion that they had it in their power not to perform the act.

We exempt the insane or the child, because we believe them devoid of moral freedom and determined inevitably by the motives that happened to act on them. This belief is so strong, or ingrained, or just plain true that determinists have to admit that the meaning of these terms will, according to their view, have to be changed. But this is to admit that their theory is in direct conflict with universal psychological facts. It thereby stands disproved. Again, it may be argued that, if logically followed out, the determinist doctrine would annihilate, or leave no room for, human morality, and consequently that such a theory cannot be true. (Such a view would then correspond to fatalism).

ii) Psychological Arguments for Free Will

Consciousness testifies to our moral freedom. We feel ourselves to be free when exercising certain acts. We judge afterwards that we acted freely in those acts. We distinguish them quite clearly from experiences in which we believe we were not free or responsible. The conviction is not confined to the ignorant; even the determinist psychologist is governed in practical life by this belief. Henry Sidgwick states the fact in the most moderate terms, when he says:

"Certainly in the case of actions in which I have a distinct consciousness of choosing between alternatives of conduct, one of which I conceive as right or reasonable, I find it impossible not to think that I can now choose to do what I so conceive, however strong may be my inclination to act unreasonably, and however uniformly I may have yielded to such inclinations in the past "

- H. Sidgwick, Methods of Ethics

The weight of such evidence is best judged by carefully studying the various mental activities in which freedom is exercised. Amongst the chief of these are: voluntary attention, deliberation, choice, and sustained resistance to temptation. These mental activities have been analysed at length by philosophers such as David Hume, JS Mill, William James, and of course Sidgwick himself. (You may, nonetheless, prefer to think them out with concrete examples of your own inner experience and feel or intuit the force or power of the notions raised for examination.)

The main objection to the range of psychological arguments for free will is stated in the assertion that we can be conscious only of what we actually do, not of our ability to do something else. The reply is that we can be conscious not only of what we do, but of how we do it; not only of the act but of the mode of the act. Observation reveals to us that we are subjects of different kinds of processes of thought and volition. Sometimes the line of conscious activity follows the direction of spontaneous impulse, the preponderating force of present motive and desire; at other times we intervene and exert personal causality (in other words, we do something about it).

Consciousness testifies (through our being conscious of some relevant such and such) that we freely and actively strengthen one set of motives, resist the stronger inclination, and not only drift to one side but actively choose it. In fact, we are sure that we sometimes exert free volition, because at other times we are the subject of conscious activities that are not free, and we know the difference. Again, it is urged that experience shows that human beings are determined by motives, and that we always act on this assumption. The reply is that experience proves, or at least shows, that human beings are influenced by motives, but not that they are always inexorably determined by the strongest motive. It is alleged that we always decide in favour of the strongest motive. This is either untrue, or the barren statement that we always choose what we choose. A free volition is "a causeless volition". Our self, or our mind itself, is the cause. (Other objections include philosophical ones from the point of view of fatalism and scientific ones from such general principles as the Law of the Conservation of Energy.)

4 The Nature and Range of Free Will: Have We Moral Liberty?

Free will does not mean capability of willing in the absence of all motive, or of arbitrarily choosing anything whatever. It is not non-determinism, randomness or non-causality, in any shape or form. The rational being is always attracted by what is apprehended as good. Pure evil, misery as such, is something a human being could not properly, rationally, desire. However, the good presents itself in many forms and under many aspects such as the pleasant, the prudent, the right, the noble, the beautiful, and in reflective or deliberate action we can choose among these.

Nor does the doctrine of free will imply that a human being is constantly exerting this power at every waking moment, any more than the statement that ‘we are rational animals’ implies that we are always reasoning. Much the larger part of our ordinary lives are administered by the machinery of reflex action, the automatic working of the organism, and acquired habits. In the series of customary acts which fill up our day, such as rising, meals, study, work, etc., the large majority are, by and large, merely "spontaneous" and are proximately determined by their antecedents, according to the combined force of character and motive. There is nothing to arouse special volition, or call for interference with the natural current, so the stream of consciousness flows smoothly along the channel of least resistance. For such a series of acts we are responsible, though not because we exert deliberate volition at each step, but because each step is free in causa (there is/was a choice about bringing them about). They are so free in causa, because we have either freely initiated them, or approved them from time to time when we adverted to their ethical quality, or because we freely acquired the habits that now accomplish these acts. It is then especially when some act with a specially moral complexion is recognised and acknowledged as good or evil that the exertion of our freedom and the exercise of our free will is brought into play. This may not, of course, occur to everyone at the same time or in the same way. It is open to individual circumstance and is in no way rigidly determined.

In sum, with reflective advertence to the moral quality of the act comes the apprehension that we are called on to decide between right and wrong. It is then that the consciousness, or awareness, arises within us that we are choosing freely, and this carries with it the subsequent conviction both that the act was in the strictest sense our own, and that we are responsible for it; and as for moral actions, so for all other free actions of human beings.


D Dennett, 1984, Elbow Room: The Varieties of Free Will Worth Wanting. The MIT Press

D Hofstadter, 1982, Can creativity be mechanized?, Scientific American, 247, 20-29

D Hume, 1748, An Enquiry Concerning Human Understanding, Harvard Classics Volume 37, Click here for online edition

W James, 1890, Principles of Psychology Click here for online edition

R Lewontin, 1991, Biology as Ideology: The doctrine of DNA. New York: Harper Collins

JS Mill - On Liberty (1869) and Utilitarianism

P Molenaar, D Boomsma and C Dolan, 1993, A third source of developmental differences, Behavior Genetics, 23, 519-524

R Plomin, J DeFries, and G McClearn, 1990, Behavioral Genetics: A primer (2nd ed.). New York: Freeman. Click Here to buy from Amazon

H. Sidgwick, 1874, The Methods of Ethics Click here for online edition

D Woodridge - The Machinery of the Brain


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