The Prior Environmental Fitness of Nature: An Argument for the Existence of God

In the sixteenth century, the Polish astronomer Nicolaus Copernicus (1473-1543) developed a model of the solar system which placed the Sun, rather than the Earth, at its center. Shortly before his death in 1543, Copernicus published his book, On the Revolutions of the Celestial Spheres [1]. This sparked the beginning of a major scientific paradigm shift and marked the dawn of the Copernican Revolution, ultimately leading to the widespread abandonment of the Aristotelian geocentric model of the solar system and the acceptance of the heliocentric model in its place. Today, the Copernican revolution is thought by many to have dethroned man from his central place in nature.

Recent scientific breakthroughs, however, have brought the debate over man’s place in the cosmos full circle. Over the past several decades, science has amassed considerable evidence of design in nature – evidences which may be drawn from both the physical and life sciences. This evidence suggests, contrary to popular wisdom, that the Universe was made with us in mind – that it was intended for beings like ourselves. In this article, we will consider a sample of evidences that force us to reconsider man’s place in the Universe.

In my published work and public lectures, I have discussed in detail the incredible evidence of design in the life sciences. In this article, I will review another class of teleological arguments that has scarcely received attention in contemporary treatments of this subject — that is, the argument from the prior environmental fitness of nature for life – and, in particular, advanced life resembling our anatomy and physiology. This class of teleological argument stands largely independently of the better-known arguments from cosmic fine-tuning. So vast is this evidence for teleology in nature that I can only survey a brief sample here. For a much more detailed review, however, I refer readers to Michael Denton’s excellent work, including Nature’s Destiny [2], Fire-Maker [3], Children of Light [4], The Wonder of Water [5], The Miracle of the Cell [6], and The Miracle of Man [7]Older architects of this argument included the early twentieth century physiologist Lawrence Henderson (in his classic, The Fitness of the Environment [8]) and Arthur Needham (in his book, The Uniqueness of Biological Materials [9]).

The Structure of Teleological Arguments

Before reviewing specific instances of teleology in nature, it is necessary to give an account of precisely why the cases discussed in this essay confirm a design thesis. This helps us to distinguish the reasoning offered in this article from a fallacious species of argument commonly referred to as ‘god of the gaps’ arguments, wherein the protagonist attempts to infer the involvement of a supernatural agency on the sole basis of his or her incredulity about such a feature having otherwise arisen. Any adequate epistemology of design detection must allow us to specify examples of physical phenomena that are surprising and hitherto unexplained and yet fail to justify an inference of design.

As a card-carrying Bayesian, I would contend that the strength of the evidence for a proposition is best measured in terms of the ratio of two probabilities, P(E|H) and P(E|~H) — that is, the probability of the evidence (E) given that the hypothesis (H) is true, and the probability of E given that H is false. That ratio may be top heavy (in which case E favors H), bottom heavy (in which case E favors ~H), or neither (in which case E favors neither hypothesis, and we would not call it evidence for or against H). Bayes’ Theorem is a mathematical tool for modelling our evaluation of evidences to appropriately apportion the confidence in our conclusions to the strength of the evidence. To take an example, suppose that P(E1|H) = 0.2, but P(E1|~H) = 0.04. Then the ratio P(E1|H)/P(E1|~H) has the value of 5 to 1. If there are multiple pieces of independent evidence of the same sort, their power accumulates exponentially. Five such pieces would yield a cumulative ratio of 3125 to 1. If the initial ratio were 2 to 1, ten pieces of independent evidence would have a cumulative power of more than 1000 to 1. By expressing it in mathematical terms like this, it becomes apparent how small pieces of evidence, no single piece by itself of very great weight, can combine to create a massive cumulative case. 

This form of reasoning is used routinely in the discipline of forensic science. For instance, the presence of a defendant’s fingerprints on a murder weapon may be taken as evidence for the hypothesis of guilt over the hypothesis of non-guilt because the probability of the defendant’s fingerprints being on the murder weapon is significantly higher on the hypothesis that the defendant is guilty than on the hypothesis that he is not guilty.

It is important to bear in mind that it is not necessary, in order for a proposition to be evidentially favored by a piece of data, for the hypothesis to strongly predict the data. For example, the hypothesis that you were in the vicinity of nuclear plant does not strongly predict that you will have radioactive poisoning (few such workers suffer this). But if you did have radioactive poisoning, it would be significant evidence that you were in the vicinity of a nuclear plant since that data is more expected (or, less surprising) given the truth of the hypothesis than given its falsehood.

How might we make a powerful case for the existence of God based on the principles elaborated upon in the foregoing? We can begin by giving an estimate of the probability of the evidence given theism and the probability of the evidence given atheism, in order to calculate the Bayes Factor. One way to frame the argument for the existence of God – the approach I will take in this article – is to consider the evidence that we self-evidently live in what I call a moral choice arena [10], defined simply as a community of persons in circumstances where they can engage in what we call moral decision-making, where they interact with other agents and grow their character in morally significant ways. On the hypothesis of theism, a moral choice arena is something that God could be plausibly expected to bring about. [11] Why? Intrinsic to God’s very character is the quality of moral goodness, and because of this it is not unlikely for an omnipotent and omnibenevolent entity to bring about the greatest goods. Since it is not implausible that the greatest goods require a community of embodied moral agents in a moral choice arena, this is something that it might be plausibly expected for God to bring about.  Recall that it is not necessary for us to show that such a state of affairs is highly probable on theism – merely that it is not particularly implausible (for I will endeavor to show that such a state of affairs is particularly implausible supposing theism to be false). One might of course ask at this juncture why God would choose to bring about embodied agents. After all, could God not have created spiritual agents that are not embodied? However, it is being embodied that amplifies our ability as agents to affect the world and each other. A world of physical pushes and pulls greatly increases the number of opportunities for free agents to morally flourish, grow their character, and co-operate with one another.

With the foregoing ideas in hand, it should now be clear that one may objectively distinguish between physical phenomena that are mysterious but fail to support a valid design inference, and those which do. For example, the wave-particle duality of the photon in quantum physics, whereby the photon exists as both a particle and a wave is certainly a highly surprising discovery, and one not well understood. Nonetheless, there is no particular reason to think that theism better predicts this phenomenon than atheism. Therefore, unlike the examples of teleology discussed in this article, the wave-particle duality of photons – despite being a mystery in physics – is not confirmatory of a theistic hypothesis.

An additional nuance that I will add to this discussion is that, in order for a conclusion to be robustly justified by the data, it is not necessary for each of the points of data to individually suffice to establish the conclusion as true. Since each data point avails to increase the posterior probability of the proposition being true, the arguments – considered in aggregate – may be sufficient to arrive at a justified conclusion even if each of the individual pieces of evidence is not. I therefore invite the reader to consider the case developed in the remainder of this article cumulatively, asking oneself whether there is enough here to be persuaded that the Universe we observe has indeed been rigged by a superintending creator.

Finally, a word must be said concerning the prior, or intrinsic probability, of theism, since the amount of evidence required to establish a conclusion as true correlates inversely with the prior probability – that is, the probability of the hypothesis given only the background information. That the prior probability of theism is not particularly low (and even relatively high) has been defended by Richard Swinburne [12] and by Calum Miller [13, 14] on the basis of the simplicity of the theistic hypothesis. Another possible approach here is to argue that the cumulative likelihood ratio informs us regarding the prior that one rejecting the conclusion would have to assign to the existence of God in order to rationally reject theism in light of the evidence. For example, supposing that the total evidence favors theism with a Bayes factor of 109 (meaning the data is 109 times more likely to exist on T than on ~T), then one rejecting the theistic conclusion would need to assign a prior of 1/109 in order to rationally reject theism.

Having argued that a moral choice arena is not too implausible on theism (e.g. within the range of 0.001 and 0.99) we have our first epistemic probability in hand. We must now address the question of whether such a state of affairs is any less plausible on atheism – and it is to this question that I now turn.

A concern that is sometimes raised concerning fine-tuning arguments such as those expressed here is that we have observations of only one Universe and therefore lack a satisfactory handle on the probability distributions. In other words, while we can confidently say that the vast majority of conceptually possible Universes are not life-permitting, we cannot determine the odds of our Universe being realized as opposed to any other. To take an analogy, this would be akin to giving an estimate of the odds of a six-headed die coming up ‘six’ without knowing whether or not the die is fairly weighted. However, even supposing that such a constraint on the properties of nature does exist, this objection only succeeds in moving the problem of fine-tuning back a level, since any underlying law or principle that constrains nature so as to be conducive to life would itself have to be a remarkable coincidence, for the reason that there are far more ways in which it could have constrained nature to be non-conducive to life.

Another common concern upon first encountering the particular class of fine-tuning argument discussed here is that one could as well see life as being adapted to the environment rather than the environment being designed to support life. Douglas Adams famously envisioned a puddle waking up one morning and marveling at the perfectly shaped hole in which it finds itself [15]. This parallel seems to me, however, to be disanalogous since – as I will endeavor to show – whereas there are essentially an infinite number of shapes of holes that are compatible with an equally large variety of shapes of puddles, there are many ways the environment could have prohibited life and very few ways in which it is compatible with life (and even fewer in which it is compatible with advanced life). In what follows, I provide a sample of the evidence that justifies this conclusion.

The Design of the Elements

Approximately 99% of the mass of living cells is composed of the non-metal elements, particularly carbon, hydrogen, nitrogen, and oxygen. These elements are essentially the only atoms that could be used to build a biochemical system, since they form strong, stable, directional chemical bonds. Critically, these covalent bonds give molecules with shape, and it is shape that is the essence of biochemistry. Since carbon and hydrogen have a similar electronegativity (a measure of how strongly atoms pull electrons towards the nucleus), they are able to share electrons equally between the two atoms, creating a nonpolar covalent bond. On the other hand, putting oxygen and hydrogen together yields a polar molecule, with the electrons spending more time near the oxygen nucleus than they do the hydrogen nucleus. The oxygen thereby has a slight negative charge, and the hydrogen a slight positive charge. This is critical to the whole organization of the cell, because it gives you the hydrophobic force, which describes the tendency for non-polar molecules to isolate themselves from contact with water. As a result, the non-polar side chains of amino acids in a protein structure become buried in the protein’s interior, while the polar side chains face outwards, interacting with water. Thus, it is the hydrophobic force that organizes the higher structure of the biological realm – assembling membranes and proteins. Charles Tanford, describing the discovery of how proteins fold, notes that “[T]he hydrophobic force is the energetically dominant force for containment, adhesion etc., in all life processes… This means that the entire nature of life as we know it is a slave to the hydrogen bonded structure of liquid water.” [16] It is a striking anthropically-friendly coincidence, then, that the very atoms that provide stable, defined, shapes (from which macromolecules can be built) also provide the hydrophobic force which is the key to assembling them into higher three-dimensional forms.

The carbon atom, the primary constituent of organic molecules, is, in several respects, uniquely fit for the assembly of the complex macromolecules found in the cell. First, due to the stability of carbon-carbon bonding, only carbon can form long polymers of itself, forming long chains or rings, while also bonding to other kinds of atoms. Though silicon can also form long chains by bonding with itself, these bonds are significantly less stable than carbon-carbon bonds. Plaxco and Gross note that “while silicon-silicon, silicon-hydrogen, and silicon-nitrogen bonds are similar in energy, the silicon-oxygen bond is far more stable than any of the other three types. As a consequence, silicon readily oxidizes to silicon dioxide, limiting the chemistry available to this atom whenever oxygen is present. And oxygen is the third most common atom in the Universe,” [17]. As Primo Levi explains, carbon “is the only element that can bind itself in long stable chains without a great expense of energy, and for life on earth (the only one we know so far) precisely long chains are required. Therefore carbon is the key element of living substance.” [18] Second, carbon is tetravalent – that is, each atom can form four covalent bonds with other atoms. Third, carbon possesses a relatively small atomic nucleus, entailing short bond distances, thereby allowing it to form stable bonds with itself as well as other atoms. This property is also possessed by the other small, non-metal atoms in period two. Carbon is able to form single, double, and triple bonds with other atoms. Nitrogen can also form single, double, or triple bonds and oxygen can form single and double bonds. Contrast this with the nonmetal atoms directly beneath them in the periodic table – silicon, phosphorus, and sulfur – which possess larger atomic radii and therefore form such bonds less easily due to multiple bonds having reduced stability. Another property of organic bonds is that their strength sits within a Goldilocks zone, being neither too strong nor too weak for biochemical manipulations in the cell. If the strength of those bonds were to be altered by a single order of magnitude, it would render impossible numerous biochemical reactions that take place in the cell. If it were too strong, the activation energy needed to break bonds could not be sufficiently reduced by enzymatic activity (enzymes strain chemical bonds by engaging in specific conformational movements while bound to a substrate). Conversely, if organic bonds were much weaker, bonds would be frequently disrupted by molecular collisions, rendering controlled chemistry impossible. Another special characteristic of carbon is that there is not much variation in energy levels of carbon bonds from one atom to the next. Robert E. D. Clark explains that carbon “is a friend of all. Its bond energies with hydrogen, chlorine, nitrogen, oxygen, or even another carbon differ little. No other atom is like it.” [19] Kevin W. Plaxco and Michael Gross further comment, “Carbon presents a fairly level playing field in which nature can shuffle around carbon-carbon, carbon-nitrogen, and carbon-oxygen single and double bonds without playing too great a cost to convert any one of these into another… Given all this, it’s no wonder that on the order of ten million unique carbon compounds have been described by chemists, which is as many as all of the described non-carbon-containing compounds put together.” [20] 

As we have seen, carbon is absolutely fundamental to life. It also happens to be – after hydrogen, helium, and oxygen – the fourth most abundant element in our galaxy. A carbon nucleus can be generated by smashing together two nuclei of helium-4 to make beryllium-8 (containing four protons and four neutrons) and then adding a further nucleus of helium to generate carbon-12 (containing six protons and six neutrons). However, beryllium is quite unstable, and can be expected to break apart into two nuclei of helium in 10-16 seconds. On occasion, prior to the breaking apart of beryllium, a third helium nucleus collides with beryllium, resulting in a carbon nucleus. As it happens, the carbon atom possesses a special quantum property called a resonance, which facilitates this process. A resonance describes the discrete energy levels at which protons and neutrons in the nucleus can exist. Indeed, it turns out that the resonance of the carbon atom just so happens to correspond to the combined energy of the beryllium atom and a colliding nucleus of helium. As Geraint Lewis and Luke Barnes explain, “if there were a resonance at just the right place in carbon, the combined energy of the beryllium and helium nuclei would result in a carbon nucleus in one of its excited states. The excited carbon nucleus knows how to handle the excess energy without simply falling apart. It is less likely to disintegrate, and more likely to decay to the ground state with the emission of a gamma-ray photon. Carbon formed, energy released… success!” [21] Without this specific resonance level, the Universe would contain relatively few carbon atoms – in 1953, this specific resonance that had previously been predicted by Fred Hoyle was discovered by William Fowler, precisely where Hoyle had predicted it would be. The oxygen nucleus also plays a crucial role in promoting the existence of both oxygen and carbon. Oxygen may be generated by colliding together carbon and helium nuclei, but oxygen’s resonance level is half a percent too low for these atoms to remain stably bound together. If the resonance level were reduced by four percent, virtually no carbon would exist. On the other hand, were it to be increased by half a percent, essentially all of the carbon would have been converted to oxygen.

It is not only the carbon atom that is especially fit for life. Though space does not allow me to provide a comprehensive treatment, I will offer a brief sample. First, the physical and chemical properties of hydrogen, oxygen and nitrogen are radically different from those of carbon. This diversity facilitates the conferring of unique properties by chemical groups such as amino (NH2), carboxyl (COOH), and methyl (CH3) groups. If these nonmetal neighbors of carbon in the periodic table possessed similar properties to those of carbon – as is the case with the majority of adjacent atoms in the periodic table – then it is doubtful that complex multicellular lifeforms could have existed.

The properties of the transition metals are also uniquely fit for their participation in the electron transport chain, which is crucial to the process of cellular respiration. Briefly, the electron transport chain involves the flow of electrons through a respiratory chain. Electrons pass through three protein complexes that are embedded in the inner mitochondrial membrane: NADH-Q oxidoreductase (Complex I); Q-cytochrome c oxidoreductase (Complex III); and cytochrome c oxidase (Complex IV). Complex I, a large multi-subunit protein, is the enzyme that catalyzes the transfer of electrons from the reducing agent (electron donor) NADH to coenzyme Q. The electrons are relayed to cytochrome c at Complex III, and Complex IV transfers the electrons to oxygen, which is thus reduced to water. Complexes I, III and IV serve as proton pumps, using the energy from electron transfer to transport protons from the matrix into the intermembrane space. The complexes utilize the energy given up by the flow of electrons. The inner mitochondrial membrane is impermeable to protons, leading to their accumulation in the intermembrane space. Like water behind a dam, this build-up of protons stores potential energy. A chemical turbine called ATP synthase then facilitates the flow of protons down their concentration gradient from the inner membrane space to the matrix, using the energy released in the process to create ATP. Essential to this process is a unique property of the transition metal atoms, namely, their possessing different redox potentials – that is, their ability to accommodate varying numbers of electrons in their outermost shells. The extent to which the outer shell is full of electrons will determine the atom’s affinity for electrons (with a less full outer shell having a stronger affinity for electrons than one that is fuller). Furthermore, the redox potential (that is, the affinity for electrons) of the transition metals “can be fine-tuned by appropriate choice of ligands to encompass almost the entire biologically significant range of redox potentials.” [22] This makes it possible to organize a chain of transition metal atoms, each with an increasing redox potential, in order for electrons to be drawn from one metal atom to the next in a series of discrete ordered steps. No other atoms, besides the transition metal atoms, have the properties needed to undertake this task. It is also noteworthy that no alternative mechanism has ever been employed in any known lifeform to generate the large quantities of ATP needed to sustain life.

Another instance of prior fitness relates to the suitability of inorganic ions for the generation of nerve impulses in more complex life forms like ourselves. Before an impulse is generated, a neuron is said to be in a state of polarization, with sodium ions (Na+) being more abundant outside the cell and potassium ions (K+) as well as negative ions being more abundant inside. The charge on the inside of the cell membrane is thus negative relative to that on the outside. A stimulus renders the membrane extremely permeable to Na+ ions, which rapidly enter the cell (up to a million ions per second can pass through an open ion channel), resulting in a reversal of charges on the membrane (referred to as depolarization). The inside now is positively charged, and the outside negatively charged. Depolarization results in the membrane becoming extremely permeable to K+ ions, which rapidly leave the cell. This is referred to as repolarization since it restores the outside positive charge and inside negative charge. Sodium and Potassium pumps subsequently return the Na+ ions outside and the K+ ions inside and the impulse is complete. This process critically depends upon the high mobility of these inorganic ions. Denton observes that “No other small particles of matter possess charge and such great mobility. Neither proteins nor any of the organic molecules in the cell have the right properties to stand in for the alkali metal ions.” [23]

The Sun’s Radiation

The oxygen that we breathe is generated by the process of photosynthesis in the chloroplasts of green plants, a process that is energized by the light from the sun. Remarkably, the radiation emitted by the sun exhibits several remarkable coincidences that make life possible. Many forms of radiation make up the electromagnetic spectrum, each possessing a different wavelength. Within the inconceivably vast range of the electromagnetic spectrum, there exists a small band of radiation that possesses the right energy levels for photochemistry – allowing animals to see and green plants to photosynthesize. This corresponds to the visual band, together with the near ultraviolet and near infrared wavelengths that are closely adjacent to it. This band represents such an incredibly small fraction of the electromagnetic spectrum that it is difficult to do it justice. Concerning the inconceivable vastness of the electromagnetic spectrum, Michael Denton notes, “Some extremely low-frequency radio waves may be a hundred thousand kilometers from crest to crest, while some higher-energy gamma waves may be as little as 10-17 meters across (only a fraction of the diameter of an atomic nucleus). Even within this selected segment of the entire spectrum, the wavelengths vary by an unimaginably large factor of 1025 or 10,000,000,000,000,000,000,000,000.” [24]. The visual region of the spectrum represents a miniscule fraction of this, lying between wavelengths of 380 and 750 nm in length. Put another way, “the ‘right light’ would be only a few seconds in a time-span one hundred million times longer than the age of the Earth, or a few playing cards in a stack stretching beyond the galaxy of Andromeda – a fraction so small as to be beyond ordinary human comprehension.” [25] It is a remarkable coincidence, then, that nearly half of the radiation emitted by the sun lies within this visual region.

As to the other half of the sun’s radiant output, this lies primarily in another infinitesimally small region of the spectrum that is adjacent to the visual region, between the wavelengths of 750 to somewhat beyond 2,500 nm. This infrared radiation provides approximately half of the essential heat that is needed to warm the atmosphere of our planet. Denton remarks, “Without it Earth’s entire surface would be a frozen wilderness far colder than the Antarctic. It is thanks to the heat of the sun (and to our atmospheric gases absorbing this heat) that water exists in liquid form on Earth’s surface and the average global atmospheric temperature is maintained well above freezing, in a temperature range which enables the chemistry of life to proceed.” [26]

Denton concludes, that “this is a genuine coincidence, as the compaction of solar radiation into the visible and near infrared is determined by a completely different set of physical laws from those that dictate which wavelengths are suitable for life and photosynthesis.” [27] One might be tempted to ask here whether, given the sheer number of stars in our Universe (conservatively estimated at 1024), our sun might be the lucky winner of a cosmic lottery. But, in fact, most stars emit the majority of their radiation in the visible and infrared region.

Of course, photosynthesis also requires that the visual light be allowed to penetrate the atmosphere and reach the ground, and that part of the sun’s infrared radiation be absorbed in order to warm our planet to the degree that photosynthesis can take place. It is an exquisitely fortuitous coincidence, then, that earth’s atmosphere not only allows penetration of almost all of the radiation in the visual region, but also absorbs a significant proportion of the infrared radiation, thereby warming the earth into the ambient range. In addition, our atmosphere absorbs the dangerous radiation on either side of the visual and near-infrared regions of the spectrum.

Finally, in order for photosynthesis to take place, the visual light must be able to penetrate water, since the light must traverse the water in the cell of any green plant in order to reach the chloroplasts. And, indeed, water – whether in its liquid, gaseous or solid form – is transparent to visual light. If the water vapor in the atmosphere or the liquid water of the cell absorbed the visual band, there could be no photosynthesis, and no aerobic form of life would exist.

Properties of Water

A plethora of other properties of water appear to be uniquely fit to support life. For example, unlike almost all other substances, water expands and becomes less dense in its solid form than it is in its liquid form. Ice has an open structure that is sustained by the hydrogen bonds between water molecules. If ice behaved like almost all other substances (a notable exception being the metal gallium, which also expands on freezing), it would sink to the bottom and the oceans would freeze from the bottom up, leading to much of our planet being permanently encased in ice – since the ice beneath the water would be shielded from the warmth of the sun’s rays. Since ice expands upon freezing, however, it insulates the water beneath the surface, keeping it in its liquid form. This property of water is essential to complex life, both marine and terrestrial.

Water is also a nearly universal solvent, and this property of water is critical to its role in dissolving minerals from the rocks. Indeed, almost all known chemicals dissolve in water to at least some extent. The solubility of carbon dioxide in water and its reaction with water to yield carbonic acid also promotes chemical reactions with these minerals, increasing their solubility.

Water also has an extremely high surface tension (second only to mercury of any common fluid). As water is drawn into fissures (as a result of its high surface tension) and expands upon freezing, the surrounding rocks are split open, thereby conferring a greater surface area for chemical weathering.

For life on land to thrive, the dissolved minerals also have to be deposited on land, which is made possible by the hydrological cycle whereby the water from the oceans evaporates into the atmosphere and returns to the ground as rain or snow. The hydrological cycle is itself made possible by water’s existence in three states (solid, liquid, and gas) in the range of ambient temperatures at the earth’s surface. This ability to exist in three different states at the ambient conditions at the earth’s surface is unique among all known substances. Were it not for this unique property of water, the land masses of our planet would exist as a barren dessert. Michael Denton remarks concerning this remarkable property of water: “the delivery of water to the land is carried out by and depends upon the properties of water itself. Contrast this with our artifactual designs, where key commodities such as clothes or gasoline must be delivered by extraneous delivery systems such as trucks and trains. Gasoline cannot deliver itself to gas stations nor clothes to clothing stores. But water, by its own intrinsic properties, delivers itself to the land via the hydrological cycle.” [28]

Various properties of water also make it an ideal medium for the circulatory system of complex organisms like ourselves. Concerning water’s supreme quality as a solvent, the early twentieth century physiologist Lawrence Henderson remarked, “It cannot be doubted that if the vehicle of the blood were other than water, the dissolved substances would be greatly restricted in variety and in quantity, nor that such restriction must needs be accompanied by a corresponding restriction of life processes.” [29]. Another characteristic of water is that its viscosity is one of the lowest of any known fluid. The pressure that is needed to pump a fluid increases proportionally with its viscosity. Therefore, if the viscosity of water were significantly increased, it would become prohibitively difficult to pump the blood through the circulatory system. Denton notes that “the head of pressure at the arterial end of a human capillary is thirty-five mm Hg, which is considerable (about one-third that of the systolic pressure in the aorta). This relatively high pressure is necessary to force the blood through the capillaries. This would have to be increased massively if the viscosity of water were several times higher, and is self-evidently impossible and incommensurate with any sort of biological pump.” [30] Given that approximately ten percent of the body’s resting energy is spent on powering the circulatory system, increasing the viscosity of water – to that of olive oil, for example – would present an insurmountable energetic challenge. The viscosity of a fluid is also inversely proportional to its diffusion rate, and so increasing the viscosity of water would have a significant impact on the rate of diffusion from capillaries to the cells of the body.

Water, furthermore, has one of the highest specific heat capacities of any known fluid. By serving to retard the cooling rate, this property conserves water in its liquid form when it comes into contact with air that is below freezing temperature. Another remarkable feature of water is its evaporative cooling effect. As water evaporates from an object’s surface, the molecules with more kinetic energy escape as a gas, whereas those with lower kinetic energy remain in liquid form. This serves to reduce the surface temperature. The evaporative cooling effect of water is in fact higher than that of any other known molecular liquid – i.e. compounds composed of two or more types of atom. This characteristic of water is particularly important for warm blooded organisms when the external temperature is warmer than their core body temperature and thus the excess heat cannot be radiated out into the environment. Instead, excess heat is lost through the evaporative cooling effect of water, maximized by numerous sweat glands on the skin surface.

Tectonic recycling

Finally, it is worth making brief note of tectonic recycling – a phenomenon that appears to be a unique feature of our planet in our solar system. As marine organisms die, they sink to the sea floor – taking with them the vital elements for life that they consumed during their lifetime – and are buried by sediment. If this process were to continue unabated, the life-giving elements would accumulate in ocean sediment on the sea floor, resulting in them eventually becoming segregated from the biosphere – ultimately rendering the oceans lifeless. The solution to this paradox is the phenomenon of subduction, whereby ocean sediment is carried down deep into the earth on the subducting slab surface. Upon reaching a particular depth, a portion of the slab melts and the elements are carried in plumes of magma back up to the earth surface where they are released through volcanoes.

An Inference to Design and Implications Regarding the Prior Probability of Biological Design

The examples surveyed in this article highlight that, of the many ways in which the Universe could have been, the number that are conducive to life are very, very rare. In fact, the instances adduced in this section are independent of the parameters that are more typically appealed to in fine-tuning arguments such as the cosmological constant or the gravitational constant. [31] Though any state of affairs is extremely improbable, the condition of our Universe is not only immensely unlikely but also special, in that the actual outcome – that is, a Universe occupied by conscious embodied agents – is precisely what one might expect to observe supposing theism to be true. The data therefore tend to confirm the theistic hypothesis. The evidence reviewed in this article also has another implication in regards to teleological arguments in the life sciences. Given the data surveyed in the foregoing that provide strong independent justification for supposing that an intelligent mind lies behind our Universe and that, moreover, that mind has an interest in creating complex physical life forms like ourselves, this background information is positively relevant to our assessment of the intrinsic, or prior, probability that this creator may act, by special divine fiat, to bring life into existence on our planet. The design hypothesis must, therefore, be considered a contender for the best explanation of life’s origins. It cannot be ruled out a priori

A quality of any good theory is its explanatory scope to give an account of multiple independent lines of evidence. The thesis of design is efficacious to explain not only each of the points of data taken individually, but also the whole set of data considered in aggregate. Even if each individual argument is by itself insufficient to justify a teleological conclusion, since it is clear that each individual piece of evidence significantly increases the plausibility of transcendent design, the arguments taken together surely suffice to establish the conclusion as probably true. The brief and woefully incomplete sample of evidences surveyed in this essay, considered cumulatively, provide strong grounds for inferring that, in the words of Sir Fred Hoyle, “a superintellect has monkeyed with physics, as well as chemistry and biology.” [32] The convergence of multiple disciplines upon this conclusion, in my judgment, presents a case worth considering in favor of this verdict.


1. Nicolaus Copernicus, On the Revolution of the Celestial Spheres (Johannes Petreius, 1543).

2. Michael Denton, Nature’s Destiny: How the Laws of Biology Reveal Purpose in the Universe (The Free Press, 1998).

3. Michael Denton, Fire-Maker: How Humans Were Designed to Harness Fire and Transform Our Planet (Discovery Institute Press, 2016).

4. Michael Denton, The Wonder of Water: Water’s Profound Fitness for Life on Earth and Mankind (Discovery Institute Press, 2017).

5. Michael Denton, Children of Light: The Astonishing Properties of Sunlight that Make Us Possible (Discovery Institute Press, 2018).

6. Michael Denton, The Miracle of the Cell (Discovery Institute Press, 2020).

7. Michael Denton, The Miracle of Man: The Fine Tuning of Nature for Human Existence (Discovery Institute Press, 2022).

8. Lawrence J. Henderson, The Fitness of the Environment: An Enquiry into the Biological Significance of the Properties of Matter (McMillan, 1913).

9. Arthur E. Needham, The Uniqueness of Biological Materials (Pergamon Press, 1965).

10. The term “moral arena” has also previously been used in this context in: Blake Giunta, “Does God Exist.” Belief Map. Accessed 1 January 2023.

11. Richard Swinburne, The Existence of God, 2nd edition (Oxford University Press, 2004), chapter 6.

12. Ibid., chapter 5.

13. Calum Miller, “Is theism a simple hypothesis? The simplicity of omni-properties.” Religious Studies vol. 52, 2016, 45-61.

14. Calum Miller, “The Intrinsic Probability of Theism.” Philosophy Compass, vol. 13, issue 10. 2018, e12523.

15. Douglas Adams, The Salmon of Doubt: Hitchhiking the Galaxy One Last Time (Del Rey, 2005), 131.

16. Charles Tanford, “How Protein Chemists learned about the Hydrophobic Factor: Protein Chemists and the Hydrophobic Factor.” Protein Science, vol. 6, no. 6, 1997, 1358-1366.

17. Kevin W. Plaxco and Michael Gross. Astrobiology: A Brief Introduction, 2nd edition (The John Hopkins University Press, 2011), chapter 1.

18. Primo Levi, The Periodic Table (Abacus, 1990), 226-227.

19. Robert E.D. Clark, The Universe: Plan or Accident? 3rd edition, (Zondervan, 1972), 97.

20. Kevin W. Plaxco and Michael Gross. Astrobiology: A Brief Introduction, 2nd edition (The John Hopkins University Press, 2011), chapter 1.

21. Geraint F. Lewis and Luke A. Barnes, A Fortunate Universe: Life in a Finely Tuned Cosmos (Cambridge University Press, 2017), 116-117.

22. Robert R. Chrichton, Biological Inorganic Chemistry: A New Introduction to Molecular Structure and Function, 2nd edition (Elsevier, 2012), 248.

23. Michael Denton, The Miracle of the Cell (Discovery Institute Press, 2020), 70.

24. Michael Denton, Children of Light: The Astonishing Properties of Sunlight that Make Us Possible (Discovery Institute Press, 2018), chapter 2.

25. Ibid.

26. Michael Denton, The Miracle of Man: The Fine Tuning of Nature for Human Existence (Discovery Institute Press, 2022), 52.

27. Ibid., 53.

28. Ibid., 34

29. Lawrence J. Henderson, The Fitness of the Environment: An Enquiry into the Biological Significance of the Properties of Matter (McMillan, 1913), 116.

30. Michael Denton, The Wonder of Water: Water’s Profound Fitness for Life on Earth and Mankind (Discovery Institute Press, 2017), 161-162.

31. Geraint F. Lewis and Luke A. Barnes, A Fortunate Universe: Life in a Finely Tuned Cosmos (Cambridge University Press, 2017).

32. Hoyle, Fred. “The Universe: Past and Present Reflections.” Annual Review of Astronomy and Astrophysics, vol. 20, 1982, pp. 1-35.