So how does one determine that a message, object, or action is the result of intelligent causation? We do this on a sub-conscious level quite often but how do we formally discern intelligent design? There have been several methodologies put forth to detect design but the one that is achieving the most press in recent times is the complexity-specification criterion offered by William Dembski, the author of No Free Lunch and several other books on intelligent design.
The complexity-specification criterion translates the question of design into the establishment of three basic attributes: contingency, complexity, and specification. According to Dembski's framework an object that satisfies all three is the result of intelligent design. [Note that the framework is clearly susceptible to false negatives - as an intelligent agent can create an entity that fails to meet the criteria.]
Contingency
Contingency is established by demonstrating that a message, object, or action is irreducible to any underlying physical necessity. For example, the formation of a snowflake fails to exhibit contingency because the snowflake is the result of physical laws. Contrast this with the text that you are reading now which is irreducible to the physics associated with your computer screen and monitor.
More objects that fail contingency
1. Crystals
2. Hexagonal Basalt Columns of the Giant's Causeway in Ireland
3. Tornados
Complexity
Dembski defines complexity to be a form of probability. In particular, a message, object, or action is complex when it is of sufficiently low probability. The universal probability bound associated with the complexity-specification criterion is 1 in 10^150.* This value is also equivalent to 500 bits of information as defined by mathematician and the father of modern information theory Claude Shannon.
The challenge however associated with establishing complexity is that the particular domain must be extremely well understood. And with respect to biological systems, we are probably years away from being able to produce reliable probabilities concerning their formation.
Some example probabilities
1. SETI Message in the movie Contact - 1 in 10^339
2. Single ticket winning a 6 number lotto - ~1 in 10^7
3. Formation of the minimum set of the required 239 protein molecules for the smallest
theoretical life - 1 in 10^119,879 (Rough Estimate)
Specification
Perhaps the most elusive aspect of this framework is specification. Specification is established by determining that a message, object, or action is consistent with a pattern that is narrowly defined. An example of a message that is highly specified is the number of prime numbers between 1 and 100 (which happens to be the SETI message that was used in the movie Contact). This is contrast with a message that is any number of values between 1 and 100.
[Note for those seeking more detail on this aspect of the framework there's a mathematical definition for Specification that can be found in Dembski's book titled No Free Lunch.]
*This value is derived by the following calculation: 10^80 particles in universe x 10^45 state transitions (Planck time) x 10^25 seconds in Universe.
