Are there laws in nature?

Tetsunori Koizumi, Director

While Johannes Kepler (1571-1630) is well known in the history of science for his discovery of planetary laws of motion, it was Rene Descartes (1596-1650) who explicitly and rigorously formulated the “laws of nature” in the way the term is employed in modern science. However, as one who lived in the age of transition from the medieval world of faith to the modern world of reason, Descartes did not quite remove God from his discussion of the laws of nature, for he states, in a letter he wrote in 1630, that “it is God who established the laws of nature.”1

If Descartes did not remove God from his discussion of the laws of nature, what about Isaac Newton (1643-1727), a true giant in the history of science who contributed more than anybody else to widespread acceptance of the modern concept of scientific laws. With his use of precise mathematical formulations, we would suspect that Newton had no need for God to be the lawmaker behind his laws of motion and his law of gravity. If there was need for God, it was because the world was created by him in such a way that was susceptible to mathematical formulations, as Newton wrote in his Optics published in 1704: “All these things being considered, it seems probable to me that God in the beginning formed matter in solid, massy, hard, impenetrable, moveable particles, of such sizes and figures, and with such other properties, and in such proportion to space, as most conduced to the end of which for which he formed them …”2 We also know that God appears in the famous epitaph written in 1727 for Newton by Alexander Pope (1688-1744): “Nature, and Nature’s laws lay hid in night: /God said, Let Newton be! And all was light.”

Scientists still talk about the laws of nature today, except that they no longer regard them as being established by God. As Stephen Hawking (1942- ) and Leonard Mlodinow (1954-) state in their The Great Design, “Today most scientists would say a law of nature is a rule that is based on an observed regularity and provides predictions that go beyond the immediate situations upon which it is based.”3 Thus, a law of nature is not something that is established by God but is something that is discovered and formulated by the scientist based on his/her careful observation of a natural phenomenon. And just as was the case with Newton, scientists today also try to express their laws of nature in mathematical terms that would capture observed regularities behind natural phenomena. The laws of nature in this modern sense are to be found in all of the natural sciences, from physics to chemistry to biology.

The ubiquity of the laws of nature in scientific disciplines shows that regularities do exist behind natural phenomena. The prevalence of regularities behind natural phenomena that enables scientists to predict beyond the immediate situations observed leads to the idea of determinism, the idea that all physical systems in nature follow deterministic laws. The laws of nature in classical physics such as Newton’s laws of motion and his law of gravity are outstanding examples of deterministic laws of nature.

While the idea of determinism has played an important role in classical physics, does the idea still play an important role in physics today, especially in the wake of the revolutionary implications of quantum mechanics regarding the uncertainty of the scientist’s observation of natural phenomena at the subatomic level? To be sure, scientists no longer believe that all physical systems consist of solid and impenetrable particles whose behavior is describable and predictable by deterministic laws. However, scientists have not quite abandoned the idea of determinism. In fact, quantum mechanics simply has led to a new form of determinism: “Given the state of a system at some time, the laws of nature determine the probabilities of various futures and pasts rather than determining the future and past with certainty.”4

If the laws of nature, while still regarded as deterministic, no longer determine the future and past with certainty, in what sense do they represent universal truths about the way nature works? In other words, is a law of nature a truth universally acknowledged? The answer has to be: No. Just like the opening sentence in Pride and Prejudice by Jane Austin (1775-1817), “a single man in possession of a good fortune must be in want of a wife,” is not a truth universally acknowledged outside of a specific society in which Mr. Bingley operated, the validity of a law of nature depends on a specific context in which the scientist makes his/her observations and formulates his/her theories. Taken out of a specific context of inquiry in which the scientists operates, which a Belgian physicist Leon Rosenfeld (1904-1974) called “the domain of validity”,5 a law of nature does not represent a truth about nature. If that were the case, should we perhaps abandon the use of the term, “laws of nature”, altogether? Should we, instead, talk about the laws of classical mechanics, the laws of quantum mechanics, the laws of thermodynamics, and so on, in order to make explicit the domain of validity for each law, which is derived, if not invented, by the scientist based on his/her insight, observation, and reasoning?

The idea that the laws of nature no longer express certitude as they used to in classical mechanics is clearly stated by another Belgian physicist Ilya Prigogine (1917-2003): “In the classical view—and here we include quantum mechanics and relativity—laws of nature express certitudes. When appropriate initial conditions are given, we can predict with certainty the future, or “retrodict” the past. Once instability is included, this is no longer the case, and the meaning of the laws of nature changes dramatically, for they now express possibilities or probabilities.”6 This is so because nature, or the world around us, is a dynamic process full of instabilities: “In our world, we discover fluctuations, bifurcations, and instabilities at all levels. Stable systems leading to certitudes correspond only to idealizations, or approximations.”7

If the laws of nature no longer express certitudes, why do scientists still search for them? The scientists’ preoccupation with searching for the laws of nature stems, in a way, from the preoccupation of the people in the West to seek something where there is nothing, to seek order where there is chaos, to seek action where there ought to be inaction, in their conception of the relationship between man and nature. Prigogine’s conception of the laws of nature as expressing possibilities or probabilities leads us to the conception of nature as a self-organizing system, which comes very close to the Eastern conception of nature as “what is by itself ” In the tradition of Eastern philosophy, nature is seen as a spontaneous, self-generating process, which can be only metaphorically described by a term such as Tao or samsara. Although Buddhists readily admit that we cannot conceive of all causes and conditions, the only law of nature meaningful for them is that everything in the world around us exists only as part of a composite entity that undergoes changes with the constantly evolving network of causes and conditions, which is nature. What is required of us, then, is to acquire “the wisdom to see into the arising and passing away of phenomena”, the wisdom to see how we are integrally involved in that constantly evolving network of causes and conditions around us.

  1. Kenny, Anthony (ed.), Descartes’ Philosophical Letters, Oxford: Clarendon Press, 1970.
  2. Newton, Optics, Britannica: Great Books of Western World, 1952, p.541
  3. Stephen Hawking and Leonard Mlodinow, The Grand Design, New York: Bantam Books, 2010, Chapter 2.
  4. Hawking and Mlovinow, ibid., Chapter 4.
  5. Leon Rosenfeld, “Unphilosophical Considerations on Causality in Physics”, R.S. Cohen and J.J. Stachel (eds.), Boston Studies in the Philosophy of Science, vol. 21, Dordrecht: Reidel, 1979, pp. 666-690.
  6. Prigogine, Ilya, The End of Certainty: Time, Chaos, and the New Laws of Nature, New York: Free Press, 1996, p.4.
  7. Prigogine, ibid., p. 55.