In their new book, The Grand Design, Stephen Hawking and Leonard Mlodinow defend scientific determinism, which they define as follows:
Given the state of our universe at one time, a complete set of laws fully determines both the future and the past. This would exclude the possibility of miracles or an active role for God. …It is, in fact, the basis of all modern science, and a principle that is important throughout this book. A scientific law is not a scientific law if it holds only when some supernatural being does not intervene (30). 1
They essentially argue that the laws of nature must hold true in all cases without being overridden by divine intervention. Scientific laws must operate without exceptions, except “under a stipulated set of conditions (28).”
The authors then apply scientific determinism in rejecting human free will. They reason that humans live in the universe and interact with it. Therefore scientific determinism must apply to them just as it applies to the rest of the universe. They argue, “Though we feel that we can choose what we do, our understanding of the molecular basis of biology shows that biological processes are governed by the laws of physics and chemistry and therefore are as determined as the orbits of the planets” (31-32). For support they point out that electrical stimulation of the brain can create false sensations. They conclude, “…so it seems that we are no more than biological machines and that free will is just an illusion (32).”
They then argue that human behavior, though it is determined by nature, is impossible to predict in practice due to the complexity and the numerous variables involved. They instead propose applying an “effective model” (a model which can explain an overall phenomenon without explaining all underlying processes in detail) to human behavior. For example, we cannot calculate all the gravitational attractions between the atoms of a human body and the atoms of the earth, but we can still describe the overall gravitational attraction between a person and the earth. Chemistry provides an effective model to explain how atoms and molecules interact without the explaining the interactions in complete detail. Hawking and Mlodinow argue:
In the case of people, since we cannot solve the equations that determine our behavior, we use the effective theory that people have free will. The study of our will, and of the behavior that arises from it, is the science of psychology. …That effective theory is only moderately successful in predicting behavior because, as we all know, decisions are often not rational or are based on a defective analysis of the consequences of the choice. That is why the world is in such a mess (33).
If a person begins with scientific determinism and a no-exceptions view of the laws of nature, then it makes sense that he would conclude that free will is illusory. However, this still causes many problems for the Hawking and Mlodinow argument. No doubt they would try to persuade people of the veracity of their view. Presumably this is at least one reason for writing this book. However, if free will is an illusion, what is the point of persuasion? If Hawking and Mlodinow are correct, then a person agrees or disagrees, is persuaded or not persuaded, only because he was scientifically determined to do so. Hawking and Mlodinow hold their view and wrote their book only because they were scientifically determined to do so.
Hawking and Mlodinow say that decisions are often irrational and that this is why “the world is in such a mess (33).” If someone’s decision is irrational, should we try to persuade him to be rational? What is the point if he is only doing what he is scientifically determined to do? Strictly speaking, he is not even making a decision. How do we judge what is and is not rational if we do not even choose one option over another? Rationality and persuasion are meaningless in such a system. (For an analysis of the foundation of logic, see The Foundation of Logic in the Nature of God. 2) So what if the world is in such a mess? Even if standards of mess vs. non-mess have any meaning in a Hawking-Mlodinow model, each person would only be holding his scientifically determined standard and either following or violating it in a scientifically determined manner.
Also, what is the point of employing an “effective theory” of human free will? Hawking’s and Mlodinow’s examples of gravity and chemistry do not provide a helpful analogy. In these illustrations, gravity and chemistry provide generalizations of observable processes. However, if free will is ultimately an illusion, as Hawking and Mlodinow argue, then an “effective theory” of free will is no more than an illusion, applying what Hawking and Mlodinow have already rejected.
Hawking and Mlodinow also seem to contradict themselves near the end of this book. They speculate on the possibility of meeting an alien being and how to determine that it has free will and is not simply a robot. They say:
The behavior of a robot would be completely determined, unlike that of a being with free will. Thus one could in principle detect a robot as a being whose actions can be predicted (178).
However, they say that there are too many particles in a complex being to do calculations to predict its behavior. We can say it has free will but merely as “an admission of our inability to do the calculations that would enable us to predict its actions (178).”
Now hold on a minute. Did they not argue that human behavior is causally determined due to scientific determinism and a no-exceptions view of the laws of nature? That being the case, why do they even speculate about determining whether an alien has free will? If free will is an illusion, then an alien has no free will. Of course, if Hawking and Mlodinow do meet an alien, they may conclude that it has free will, but only because they were scientifically determined to make that conclusion. On the other hand, it is possible that Hawking and Mlodinow consider the possibility of an alien with free will in a purely hypothetical manner, but this raises the question of why they would do so if they believe that free will is ultimately an illusion.
Maybe they would try to resolve this contradiction by appealing to model-dependent realism. They explain:
Model-dependent realism short-circuits all this argument and discussion between realism and anti-realism schools of thought. According to model-dependent realism, it is pointless to ask whether a model is real, only whether it agrees with observation. If there are two models that both agree with observation, like the goldfish’s picture and ours, then one cannot say that one is more real than another.
One can use whichever model is more convenient in the situation under discussion (45-46).
They also say that the simpler theory has an advantage (47, 52) and that whichever model that best explains present observations is the best theory (50-53). So would they vacillate between denying and affirming free will according to the circumstances? However they attempt to resolve this problem, it seems that Hawking and Mlodinow find it difficult to live with the consequences of their arguments.
Christians, however, affirm that God created mankind and created them in His image, which includes a will. Christians disagree on the extent to which mankind’s fallen nature has affected his free will and reasoning ability and on the exact relationship between human free will and divine sovereignty, but Christians nonetheless reject a strict determinism that precludes free will in any form. Under the assumption of mankind’s creation by God, the existence of free will makes sense, both in theory and in practice.
- 1. All citations refer to Hawking S and Mlodinow L (2010) The Grand Design, Bantam Books, New York.
- 2. Middleton H (2010 Mar) The Foundation of Logic in the Nature of God. < http://tasc-creationscience.org/sites/default/files/newsletters/2010/mar10.pdf > Accessed 2011 Sep 09