Debate over Natural Theology

Guide for this week:
Defence of natural theology
Criticism of natural theology
Study questions for natural theology

Readings for this week:
extract from William Paley's defence of natural theology.
extract from David Hume's critique of natural theology

Defence of Natural Theology

With this set of readings we begin to look at a controversy which is preliminary to that surrounding evolution, but important for it. Before Darwin, up to and past Linnaeus -- indeed, up to the middle of the 19th century -- the dominant paradigm -- or reigning theory -- of species was that of special creation. This theory held that:

  1. Species were created by an omnipotent being, God, in their present form and with their current abilities. Neither form nor abilities change over time.
  2. Species so created are perfectly adapted to their environment, and are able to live their lives in the surroundings chosen for them by their Creator.

It should be noted that almost all biologists (the term then used was "naturalists" or "natural historians") accepted this theory, for which the following evidence was brought to bear:

  1. Nobody has observed a species appear.
  2. Nobody has observed a species change.
  3. Nobody has observed a species disappear.

The conclusion is that species are specially created.

The situation was similar to that which earlier had led the ancient Greeks, and 2000 years of scientists, to believe that the sun revolves around the earth, which is stationary at the middle of the universe:

  1. Everybody feels that the earth does not move, based on everyday experience of the ground upon which we walk.
  2. Everybody sees that the sun rises and sets every day, implying that it revolves about the earth.
  3. Everybody sees that the stars -- which are luminous bodies like the sun -- describe a semicircle each night around the earth in the visible part of the sky (implying that they do the same in the other hemisphere, forming a complete circle).

The conclusion is that the sun circles the earth.

In both these cases (geocentric cosmology, and special creation), common sense and perceptual evidence support theories which are later replaced by ones which appeal to processes not visible to the senses and which are in some degree counter-intuitive. More on this later.

The theory of special creation -- a specific biological theory about the origin and development of species -- was buttressed theoretically by the more general theory known as "natural theology". Natural theology -- which can be traced back to Augustine in later antiquity and Aquinas in the middle ages, holds the following: The existence of a natural world which is complex and harmonious is evidence for a divine being who has created the world.

In other words, in natural theology, we reason back from natural phenomena to a supernatural creator; or again, from natural effects (celestial bodies, biological organisms) to a supernatural cause (a divine being). Here I use the term "supernatural" in the logical sense of "above and beyond the natural", and not in any pejorative or demeaning sense. One can arrive at knowledge of God through sources other than natural theology -- revealed theology, for example, depends on faith and revelation, not observation and science.

Natural theology, then, is logically a higher level theory than special creation: natural theology is a general approach to reasoning from the natural to the divine, while special creation is a particular act of divinity with respect to biological species in nature. One of the best expositions of this viewpoint was presented in William Paley's Natural Theology which appeared in 1802 and went through many editions. Paley was a minister with an interest in natural history, and in his work argued by analogy as follows:

  1. We distinguish between a rock we find in our path, whose origin is by chance, and a watch, which upon examination is readily seen to be work of design.
  2. Now, an organism or living being is more like a watch than a rock, for its complexity of organization and suiting of form to function cannot be by chance.
  3. Therefore, we conclude that organisms are designed.
  4. But a design presupposes a designer. In the case of the watch, the designer is the watchmaker. In the case of the world and all its species, the designer is a divine watchmaker -- God.

Click here to read Paley's argument.

This fits very nicely with the Renaissance/Enlightenment view of God as divine "watchmaker", and the universe as a mechanism created by him. Natural theology can be considered as the dominant world view of scientists in both physics and biology in England from the 1690s to the time of Darwin.

John Ray, a taxonomist preceding and influencing Linnaeus, published the first major natural theology work by a practicing scientist in his Wisdom of God Manifested in the Works of Creation, published in 1691.

That same year, Robert Boyle, the chemist who discovered the gas pressure law and argued for an atomistic concept of matter, died. In his will, he left money for the establishment of a lecture series on natural and revealed theology, to be given each year in London area churches. The mandate for the lecture also called for a polemic "proving the Christian Religion against notorious infidels, viz. Atheists, Theists, Pagasns, Jews, and Mahometans, not descending lower to any controversies that are amongst Christians themselves." In the age of John Locke, it was enough to be tolerant among Christian denominations; those outside were subject to polemical critique. Most of the Boyle lectures were on revealed theology, but of those few on natural theology, some were quite important:

Cover of John Ray's work on natural theology (left), and Newton's letters to Bentley (right)

  1. In 1692 Robert Bentley presented the first Boyle lecture, "The Folly and Unreasonableness of Atheism", in which he refuted non-Christian views, all of which he considered as "atheistic". For help on matters of natural theology, he turned to none other than Isaac Newton, who suggested the following interventions of deity in the celestial world: (i) to create each planet and place it in its orbit (thereafter, the planet followed the law of gravitation); (ii) to make sure that planets do not crash into each other (through intersecting orbits); and (iii) to make sure that stars do not fall into each other (because of mutual gravitational attraction).

  2. William Derham delivered a very popular lecture series, one in 1711-12 (published 1713), entitled "Physico-theology: or, A demonstration of the being and attributes of God, from his works of creation.". This was followed by another work, more specialized book that considered only the heavenly bodies, entitled "Astro-theology, or, A demonstration of the being and attributes of God from a survey of the heavens". (1715).

  3. The Boyle lectures continued, with less than year frequency after about 1800, until 1961.

    The Rev. Francis Henry, Earl of Bridgewater, died in February of 1829 and left the sum of 8000 pounds sterling to be divided among eight authors for the purpose of publishing a series of volumes "On the Power, Wisdom and Goodness of God, as manifested in the Creation," to be illustrated by arguments from all branches of natural philosophy. The following volumes were published in this series, just before Darwin left on the Beagle voyage:

    Natural Theology did not expire after Darwin -- but it did take a modified form in England, including evolution as one of the natural phenomena it took as evidence for Deity! Given the controversy in America, this seems curious -- but very prominent scientists took the matter very seriously. The most important series, still in progress, is the Gifford Lecture Series, begun in 1891. This included a work "Emergent Evolution" (1923) by Conwy Lloyd Morgan, one of the founders of modern comparative psychology. In it, Lloyd Morgan developed a new philosophy of evolution based on the emergence of novelties (qualitatively new phenomena). We'll return to a modified version of this in our last discussion of the course.

    Criticism of Natural Theology

    A major criticism of natural theology was penned by the Scottish philosopher, David Hume, in the 1760s and 1770s. He entitled his work: Dialogues Concerning Natural Religion. It was published posthumously, as Hume was reticent to differ from public opinion too severely while he was still alive. The work, one of the best written dialogues in philosophy, features three speakers: a defender of revealed religion (Demea), a defender of natural theology (Cleanthes), and sceptic, unconvinced by either (Philo). Philo adduces the following arguments against natural theology:

    (1) From a natural world, one cannot reason backwards to a supernatural creator. At best, one has to admit that the creator of the world (if there is just one) is more intelligent than his creations. But for Hume, this does not rule out a more intelligent natural creator of the world, or a divine creator who is not all-knowing, and therefore different from the Christian God.

    (2) From an imperfect world, it is impermissible to reason back to a perfect creator; from a mortal world, it is impermissible to reason back to an immortal creator; from a finite world, it is impermissible to reason back to an infinite creator; and from a world containing many things, it is impermissible to reason back to a single creator.

    Hume's point is a logical one. He believes there is a flaw in the natural theology argument since the effects are not like the cause, In reasoning about cause and effect, Hume says, we have to have something natural as cause, bring about something natural as effect, not something supernatural causing something natural (or vice versa, which would be more obviously a problem). Click here to read Hume's critique of natural theology

    Hume's challenge to natural theology is of interest -- and forms part of the background to Darwin, who did two years of study at the University of Edinburgh, in Scotland.

    Study Questions

    (1) What is the key claim of natural theology?
    (2) How does Paley argue for design of living organisms in Natural Theology?
    (3) What are the critiques that Hume makes of natural theology?
    (4) What is the relationship between natural theology and special creation?