Chance and Necessity: Essay on the Natural Philosophy of Modern Biology () is a 1970 book by Nobel Prize winner Jacques Monod. Aimed at a general audience, the book describes the basic characteristics of life, reviews findings of modern biochemistry and molecular biology, and argues that life arose by blind chance guided by natural selection, could not have been predicted, and does not have a higher purpose. The author concludes that traditional philosophical or religious systems of value, explanation and meaning are untenable, and advocates for an "ethic of knowledge": committing to objectivity in the pursuit of knowledge.
According to the introduction, the book's title was inspired by a line attributed to Democritus, "Everything existing in the universe is the fruit of chance and necessity."
Summary
Monod starts the preface of the book by saying that biology is both marginal and central. He goes on to explain that it is marginal because the living world is only a fraction of the universe. Monod believes the ultimate aim of science is to "clarify man's relationship to the universe" (Monod, xi), and from that reasoning he accords biology a central role. He goes on to state that he does not intend to make a thorough survey of modern biology but rather to "bring out the form of its key concepts and to point out their logical relationships with other areas of thought…it is an avowed attempt to extract the quintessence of the molecular theory of the code" (Monod, xiii). Monod stresses the importance of the molecular theory of the genetic code as a physical theory of heredity and brands it as the "secret of life". He continues to explain how this important discovery has made it the duty of scientists to share with and enhance other disciplines of thought such as philosophy. Toward the end of the preface Monod offers an apology for any overly tedious or technical sections. He also warns that some ethical and political ideas he presents may seem naïve or ambitious but then states "Modesty benefits the scientist, but not the ideas that inhabit him and which he is under the obligation of upholding" (Monod, xiv). In the last paragraph of the preface, Monod explains that his essay developed from the Robins Lectures that he gave in 1969 at Pomona College.
Of strange objects
Monod starts off chapter I entitled "Of Strange Objects" with a consideration of the difference between natural and artificial objects and states that "the basic premise of the scientific method... [is] that nature is objective and not projective" (Monod, 3). Through a series of thought experiments and rhetorical questions, he leads the reader on a difficult path to three characteristics of living beings. One is teleonomy which Monod defines as the characteristic of being "endowed with a purpose or project" (Monod, 9). Another is autonomous morphogenesis, which points out that a living being's structure results from interactions within the being, as opposed to the external forces that shape artificial artifacts. Monod offers a single exception to this last criterion in the form of a crystal and, at this point, he states that the internal forces that determine structure within living beings are "of the same nature as the microscopic interactions responsible for crystalline morphologies" (Monod, 11), a theme that he promises to develop in later chapters. The last general property Monod offers up as distinguishing living organisms is reproductive invariance which is the ability of a living being to reproduce and transmit the information corresponding to their own highly ordered structure. The author defines the primary telonomic project "as consisting in the transmission from generation to generation of the invariance content characteristic of the species" (Monod, 14) (the preservation and multiplication of the species). Monod later retracts autonomous morphogenesis (spontaneous structuration) as a property of living beings and says instead that it should be thought of as "mechanism" leaving two essential properties of living beings: reproductive invariance and structural teleonomy. He then brings up and defends against a possible thermodynamic objection to reproductive invariance and points out the extreme efficiency of the teleonomic apparatus in accomplishing the preservation and reproduction of the structure. Here the author restates that nature is objective and does not pursue an end or have a purpose and he points out an apparent "epistemological [the study of the origin, nature, methods, and limits of human knowledge] contradiction" between the teleonomic character of living organisms and the principle of objectivity. With that cliffhanger of internal intellectual struggle Monod ends chapter one.
Vitalisms and animisms
In chapter two "Vitalisms and Animisms" Monod states that invariance must have preceded teleonomy, a conclusion reached by the Darwinian idea that teleonomic structures are due to variations in structures that already had the property of invariance and could therefore preserve the effects of chance mutations. He offers the selective theory as being consistent with the postulate of objectivity and allowing for epistemological coherence. The author then says that in the rest of the chapter he will address religious ideologies and philosophical systems that assume the reverse hypothesis: that invariance developed out of an initial teleonomic principle (this defies the principle of objectivity).
He divides these theories into vitalist, in which the teleonomic principle operates only in living matter (there is a purpose/direction in which living things alone develop), and animist, in which there is a universal teleonomic principle (that is expressed more intensely in the biosphere and therefore living beings are seen as products of universally oriented evolution which has culminated in mankind). Monod admits he is more interested in animism and will therefore devote more analysis to it. He briefly discusses the murky metaphysical vitalism of Henri Bergson and then discusses the scientific vitalism of Elsasser and Polanyi which contend that physical forces and chemical interactions that have been studied in non-living matter do not fully account for invariance and teleonomy and therefore other "biotonic laws" are at work in living matter. The author points out that the scientific vitalist argument lacks support and that it draws its justification not from knowledge or observations but from our present day lack of knowledge. He goes on to point out that today the mechanism of invariance is sufficiently understood to the point that no non-physical principle ("biotonic law") is needed for its interpretation.
Monod next points out that our ancestors had a history of animating objects by giving spirits to them so as to bridge the apparent gap between the living and non-living. To them, a being made sense and was understandable only through the purpose animating the being and so, if mysterious objects, such as rocks, rivers, rain, and stars, exist it must also be for a purpose (essentially there are no inanimate objects to them). The author says that this animist belief is due to a projection of man's awareness of his own teleonomic functioning onto inanimate nature. Nature is explained with the same conscious and purposive manner as human activity. Monod points out that this animist line of thought is still present in philosophy that makes no essential distinction between matter and life and frames biological evolution as a component of cosmic evolution (evolutive force operating throughout the entire universe). He contends that these lines of thought abandon the postulate of objectivity and also contain the anthropocentric illusion.
At the end of this chapter Monod states that the thesis he "shall present in this book is that the biosphere does not contain a predictable class of objects or of events but constitutes a particular occurrence, compatible indeed with first principles, but not deducible from those principles and therefore essentially unpredictable" (Monod, 43). In his view, the biosphere is unpredictable for the same reason that the particular configuration of atoms in a pebble are unpredictable. By this Monod does not mean to imply that the biosphere is not explicable from initial conditions/first principles but that it is not deducible (at best predictions could be no more than statistical probabilities of existence). He then points out that society is willing to accept a universal theory that is compatible with but does not foresee the particular configuration of atoms in a pebble but it is a different story when it comes to humans: "We would like to think ourselves necessary, inevitable, ordained from all eternity. All religions, nearly all philosophies, and even a part of science testify to the unwearying, heroic effort of mankind desperately denying its own contingency" (Monod, 44). It is this contingency of human existence that is the central message of Chance and Necessity, that life arose by chance and all beings of life, including humans, are the products of natural selection.
Maxwell's Demons
The third chapter is named "Maxwell's Demons". It starts off by stating that proteins are the molecular agents of teleonomic performance in living beings. Monod continues by writing that living beings are chemical machines, every organism constitutes a coherent and functional unit, and that the organism is a self-constructing machine whose macroscopic structure is not determined by outside forces but by autonomous internal interactions.
The author spends much of the chapter reviewing general facts of biochemistry. He explains that proteins are composed of 100-10,000 amino acids and he distinguishes between elongated fibrous proteins that play a mechanical role and the more numerous globular proteins that are folded upon themselves. He talks about the extraordinary specificity of action that enzymes display as exemplified by their ability to not only recognize a specific geometric isomer but an optical isomer as well. He points out that enzymes are optically active themselves, L isomers are the "natural" isomers, and that the specificity of action and the stereospecificity of the reaction conducted by an enzyme are the result of the positioning of the molecules with respect to each other.
Monod writes that an enzymatic reaction can be seen in two steps: The formation of a stereospecific complex between protein and substrate and the catalytic activation of a reaction within the complex (he stresses again that the reaction is oriented and specified by the structure of the complex). He next considers the energetic differences between covalent and non-covalent bonds and how the speed of a reaction is affected by activation energy. Since the activation energy of a covalent bond is high, the reaction will have a slower speed than that of a non-covalent bond (which occurs spontaneously and rapidly). The author points out that non-covalent interactions attain stability only through numerous interactions and when applied over short distances. To attain stable non-covalent interaction there is a need for complementary sites between two interacting molecules so as to permit several atoms of the one to enter into contact with several atoms of the other. In this complex, the molecule of substrate is strictly positioned by the multiple non-covalent interactions with the enzyme. Enzymatic catalysis is believed to result from the inductive and polarizing action of certain chemical groupings of the specific receptor. By virtue of an enzyme's capacity to form stereospecific and non-covalent complexes with specific substrate, the substrate is correctly presented in the precise orientation that specifies the catalytic effect of the enzyme. Monod reminds us that this reaction comes at the expense of chemical potential energy.
Microscopic cybernetics