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."
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).
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.
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.
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).
Next Monod makes reference to his own research and talks about the S-shaped non-linear curve that is characteristic of allosteric enzymes when activity is plotted against concentration of an effector (including the substrate).
Finally, it is the primary structure of proteins that we shall consult for the 'secret' to those cognitive properties thanks to which, like Maxwell's demons, they animate and build living systems" (Monod 81).
Monod mentions oligomeric globular proteins again and how they appear in aggregates containing geometrically equivalent protomer subunits associated into a non-covalent steric complex.
With mild treatment, protomers are separated and the oligomer protein loses function but, if the initial "normal" conditions are restored, the subunits will usually reassemble spontaneously.
That is why Mendel's definition of the gene as the unvarying bearer of hereditary traits, its chemical identification by Avery (confirmed by Hershey), and the elucidation by Watson and Crick of the structural basis of its replicative invariance, without any doubt constitute the most important discoveries ever made in biology."
There is a brief review of DNA whose structure is a helix with translational and rotational symmetry and if artificially separated the complementary strands will spontaneously reform.
That mutations are unpredictable, faithfully replicated, and that natural selection operates only upon the products of chance is repeated at the start of chapter seven entitled "Evolution".
He believes that rudimentary symbolic communication appeared early on and created a new selective pressure that favored development of linguistic ability and hence the brain.
Monod lastly points out the evidence to suggest the development of the cognitive function of language in children depends upon postnatal growth of the cortex.
In chapter eight, "The Frontiers," Monod captures the sense of wonderment one feels when considering the extraordinary diversity and complexity of organisms that have been brought about through billions of years of evolution.
Monod makes the point that behavior cannot be strictly separated as learned or innate since elements are acquired through experience according to an innate program and "the program's structure initiates and guides early learning, which will follow a certain pre-established pattern defined by the species' genetic patrimony" (Monod, 153).
Monod now concentrates on what he views as one of the unique properties of higher-level organisms, namely that of simulating experience subjectively so as to anticipate results and prepare action.
He ends the chapter stating "To give up the illusion that sees in it an immaterial "substance" is not to deny the existence of the soul, but on the contrary to begin to recognize the complexity, the richness, the unfathomable profundity of the genetic and cultural heritage and of the personal experience, conscious or otherwise, which together constitute this being of ours” (Monod, 159).
Once man extended his domain over the subhuman sphere and dominated his environment the main threat became other men and tribal warfare came to be an important evolutionary selection factor and this would favor group cohesion.
The author then says that due to the accelerating pace of cultural evolution, it no longer affects the genome and that selection does not favor the genetic survival of the fittest through a more numerous progeny.
He also points to scientific and ethical advances that have allowed “genetic cripples” to live and reproduce (the author regards this as suspending natural selection).
He advances the idea “that nature is objective, that the systematic confronting of logic and experience is the sole source of true knowledge” (Monod, 165).
The author believes that we contain an inborn genetic need to search out the meaning of existence and that is responsible for the creation of myths, religion, and philosophy.
He admits that the idea of objective knowledge as the only source of truth may seem austere and unattractive in that it does not provide an explanation that will calm the anxiety of man; “It wrote an end to the ancient animist covenant between man and nature, leaving nothing in place of that precious bond but an anxious quest in a frozen universe of solitude” (Monod, 170).
He says that the important message of science is that in the defining of a new source of truth which demands revision of ethical premises and a total break with the animist tradition.
By asserting the principle of objectivity, which is accepted in modern science, one is choosing to adhere to what Monod calls the ethic of knowledge.
The book ends with this thought: "The ancient covenant is in pieces; man knows at last that he is alone in the universe's unfeeling immensity, out of which he emerged only by chance.
[2] Jeffery Wicken, in Zygon: Journal of Religion & Science, described the book as a "manifesto of materialist biology in the most reductivist sense".