On The Calculation Of CSI
|March 25, 2011||Posted by MathGrrl under Intelligent Design, Mathematics|
My thanks to Jonathan M. for passing my suggestion for a CSI thread on and a very special thanks to Denyse O’Leary for inviting me to offer a guest post.
[This post has been advanced to enable a continued discussion on a vital issue. Other newer stories are posted below. – O’Leary ]
In the abstract of Specification: The Pattern That Signifies Intelligence, William Demski asks “Can objects, even if nothing is known about how they arose, exhibit features that reliably signal the action of an intelligent cause?” Many ID proponents answer this question emphatically in the affirmative, claiming that Complex Specified Information is a metric that clearly indicates intelligent agency.
As someone with a strong interest in computational biology, evolutionary algorithms, and genetic programming, this strikes me as the most readily testable claim made by ID proponents. For some time I’ve been trying to learn enough about CSI to be able to measure it objectively and to determine whether or not known evolutionary mechanisms are capable of generating it. Unfortunately, what I’ve found is quite a bit of confusion about the details of CSI, even among its strongest advocates.
My first detailed discussion was with UD regular gpuccio, in a series of four threads hosted by Mark Frank. While we didn’t come to any resolution, we did cover a number of details that might be of interest to others following the topic.
CSI came up again in a recent thread here on UD. I asked the participants there to assist me in better understanding CSI by providing a rigorous mathematical definition and showing how to calculate it for four scenarios:
- A simple gene duplication, without subsequent modification, that increases production of a particular protein from less than X to greater than X. The specification of this scenario is “Produces at least X amount of protein Y.”
- Tom Schneider’s ev evolves genomes using only simplified forms of known, observed evolutionary mechanisms, that meet the specification of “A nucleotide that binds to exactly N sites within the genome.” The length of the genome required to meet this specification can be quite long, depending on the value of N. (ev is particularly interesting because it is based directly on Schneider’s PhD work with real biological organisms.)
- Tom Ray’s Tierra routinely results in digital organisms with a number of specifications. One I find interesting is “Acts as a parasite on other digital organisms in the simulation.” The length of the shortest parasite is at least 22 bytes, but takes thousands of generations to evolve.
- The various Steiner Problem solutions from a programming challenge a few years ago have genomes that can easily be hundreds of bits. The specification for these genomes is “Computes a close approximation to the shortest connected path between a set of points.”
vjtorley very kindly and forthrightly addressed the first scenario in detail. His conclusion is:
I therefore conclude that CSI is not a useful way to compare the complexity of a genome containing a duplicated gene to the original genome, because the extra bases are added in a single copying event, which is governed by a process (duplication) which takes place in an orderly fashion, when it occurs.
In that same thread, at least one other ID proponent agrees that known evolutionary mechanisms can generate CSI. At least two others disagree.
I hope we can resolve the issues in this thread. My goal is still to understand CSI in sufficient detail to be able to objectively measure it in both biological systems and digital models of those systems. To that end, I hope some ID proponents will be willing to answer some questions and provide some information:
- Do you agree with vjtorley’s calculation of CSI?
- Do you agree with his conclusion that CSI can be generated by known evolutionary mechanisms (gene duplication, in this case)?
- If you disagree with either, please show an equally detailed calculation so that I can understand how you compute CSI in that scenario.
- If your definition of CSI is different from that used by vjtorley, please provide a mathematically rigorous definition of your version of CSI.
- In addition to the gene duplication example, please show how to calculate CSI using your definition for the other three scenarios I’ve described.
Discussion of the general topic of CSI is, of course, interesting, but calculations at least as detailed as those provided by vjtorley are essential to eliminating ambiguity. Please show your work supporting any claims.
Thank you in advance for helping me understand CSI. Let’s do some math!