Posted by: Dan | February 2, 2008

“Apparent and Sufficient Evidence for Design”

I enjoy refining my descriptions of why religious concepts of special creation are bunk, so here’s my latest.

The concept of “purposeful design,” or “final cause” as Aristotle termed it, is quite ancient. These four ways at looking at causes:

Material Cause: What the object in question is composed of (e.g. a house is composed of boards, bricks, mortar, etc.;

Formal Cause: What formal category the object is an exemplar of (e.g. any particular house is a “house” or dwelling place for people);

Efficient Cause: What immediate processes bring about the existence of the object (e.g. the carpenters, etc. are the efficient cause of the house); and

Final Cause: The purpose of the object (e.g. carpenters et al build houses “in order to” provide dwelling places for people).

Material and efficient causes are of course very relevant to modern science. But what about formal and final causes? Formal cause is rendered irrelevant, at least in biology, by what’s described as population-thinking. I.e., there is no such thing as an exemplar of anything in biology, but there is instead a spectrum of characteristics for any given species, race, or other taxa. What does this mean for evolution? Variation, as just described, is a pre-requisite for change based on natural selection. Another pre-requisite is that a population produces more progeny than can be sustained by a population, and thus not all progeny can survive to adulthood (see Malthus). The result is that some members of any population will survive better than others of the population, and the population as a whole changes (that is, evolves).

But I digress, I’m sure you know all that already, I’m just trying to clarify the role of variation in simple, easy-to-agree-on terms.


Examined in another way – is there a difference between ‘function’ and ‘purpose’? Function is usually described as a relationship between form and action; an implementation of some form, in the present tense; or a use. Function is easily discernable, so I shall move on. Purpose, however, suggests intention, direction or progress towards a goal. What intention however? What direction? Progress towards what? Progress or purpose in biology can only be discerned as an a posteriori observation based on assessment of patterns of change after the fact. That this is a fallacy goes without saying, and has been famously satirized:

‘It is demonstrated,’ [Pangloss] said, ‘that things cannot be otherwise: for, since everything was made for a purpose, everything is necessarily for the best purpose. Note that noses were made to wear spectacles; we therefore have spectacles. Legs were clearly devised to wear breeches, and we have breeches. Stones were created to be hewn and made into castles; [the Baron Thunder-Ten-Tronkh] therefore has a very beautiful castle…’ [Voltaire, Candide]

So, in conclusion, it would seem that the claims for “Apparent and Sufficient Evidence for Design” are greatly exaggerated. Moreover, they are based on ancient and out-dated rhetoric, logical fallacy, and conceited self-righteousness.

Aristotle link hat-tip: Allen MacNeill

Other related links:
Prejudice and Purpose
Ethnocentrism and Religion
We Live in a Dynamic, Evolving World
Promoting Science Literacy with Action Bioscience
Science Literacy, Discourse, and Evidence-Based Approaches to the World


  1. You forgot the most popular argument for the existence of God:
    Justbe Cause

  2. Actually, I frequently think that explaining such things to believers is a waste of time, when “I don’t believe in imaginary friends” suffices just fine.


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