The False Analogy as espoused by William Paley and under its modern guise of intelligent design can be summarised as follows:
We have (A) complex machines which show structure and order. We have (B) a complex universe, natural world and 'biological machines' which also show structure and order. We know that (A) have been created by an intelligent designer (namely us), therefore it follows that (B) must have also been created by an intelligent designer (namely God). This argument could be rephrased as:
All the things in the world we know of, that have been intelligently designed, have certain properties which conclusively demonstrate they have been intelligently designed. It follows hen, that anything which also has these properties must also have been intelligently designed.This is spurious. All we really know for certain is that humans made human artefacts. We don't know for sure that these other 'designed' things are the products of intelligence. This whole argument is circular, it Begs the Question. It assumes as its premise the conclusion it is trying to demonstrate. In essence it is saying: "Something that is designed has properties which show it was designed." This conclusion, though tautological, is acceptable. The next part of the argument is flawed: "Therefore something which shows these properties was intelligently designed."
All we know for sure, is that when humans design something, it inevitably has properties such as complexity, structure, purpose and order etc., but we cannot demonstrate that this reasoning applies in reverse, that complexity, structure, purpose and order, can only be the product of intelligent design. To do so assumes a priori, that objects which have properties such as complexity and purpose, are designed by an intelligence.
Tags: Fallacy, False Analogy, Begging the Question, Intelligent Design.