Ways of Arguing with Intelligent Design: Philosophers on Demarcation

1. Ways of Arguing with Intelligent Design: Philosophers on Demarcation Karl Popper’s Principle of Falsifiability is the position that every scientific theory must be capable of being brought into conflict with experience such that it can in principle be conclusively refuted. Thus, “It must be possible for an empirical scientific system to be refuted www.spaceandmotion.com/ Images/Ayer.jpg library.canterbury.ac.nz/ images/popper.jpg by experience”. Falsification was a key part of what he called his “negative methodology,” where evidence does not support a hypothesis, but can at most only refute it. By Zach Pirtle, Center for Biology and Society, Program in History and Philosophy of Science Creationist criticism of evolutionary theory takes many forms, but one of the more misguided claims is philosophical in nature. Intelligent Design advocate William Dembski has criticized evolution for a supposed lack of testability, and claims that if it isn’t falsifiable then it’s validity as science is undermined[1]. What does this mean to say? The question of what science is is a philosophical one. The idea of falsifiability grows out of what philosophers have called the problem of demarcation, or of delimiting science from metaphysics. To properly defend evolution one needs to reflect on demarcation. Like scientific theories, no criterion of scientific admissibility will ever be perfect, but we have choices, and should use the best criterion we have. Verifiability: AJ Ayer Meaning Criterion: Science vs Metaphysics Analyzes Propositions as a Whole Problems: Inherent methodological flaws Conclusive Verification is Impossible Falsifiability: Karl Popper Criterion of Method: Science vs Psuedo-Science Criterion Analyzes Propositions as a Whole AJ Ayer argued for the Principle of Verification: every empirical or scientific statement must in principle be capable of empirical verification in the world. In other words, every theory must in principle be conclusively verifiable in the empirical world. Ayer encounters problems, however, in his basic method, largely due to his holistic analysis of entire claims. Logical Asymmetry of Falsifiability and Verifiability: Consider “All Ravens are Black”. One could never “prove” (verify) that claim, no matter how many ravens one finds. But it takes only one non-black raven to “disprove” (falsify) it. This asymmetry underlies Popper’s argument for the superiority of falsification over verification. • Impossibility of Conclusive Falsification or Verification: No theory is made in isolation. If the overall hypothesis succeeds or fails, there could still be incorrect claims made in the supporting test assumptions. As physicist Pierre Duhem noted, one can save any hypothesis if one is prepared to sacrifice theory. • Falsification encounters problems with statistical claims. How can you conclusively falsify “The probability of a coin flipping heads is ½”? How about the statistical claims of biology? • Particular historical claims are sometimes called “existential claims” by logicians. Evolutionary biology makes many such claims about single historical instances. Popper can deal with these existential claims, but there are still problems with more complex, or “mixed” claims, that combine existential claims with universal claims. One example of a mixed proposition: “All men are mortal”. • Does Popper’s criterion place universal laws as the paradigm of science, thus putting evolution on seemingly shaky ground? While falsifiability has numerous strengths, it places an emphasis on universal laws that gives Intelligent Design critics an unfortunate (and misguided) advantage with the general public. Problems with Popper: The Duhemian Problem Falsifying Statistical Laws Particular Logical Claims Emphasis on Universal Laws Confirmability: Rudolf Carnap For Constructing a Logical Language Powerful Enough for Science Criterion of Meaning Analyzes Basic Term by Basic Term Non-Conclusive : Incremental Confirmation and Disconfirmation Inductive Approach Rudolf Carnap favored a proposal to use confirmability rather than conclusive falsifiability or verifiability.  Confirmability entails that each component part of a theory must in principle be able to aid in the incremental confirmation or disconfirmation of a predicted event. Due to the impossibility of conclusive verification or falsification, Carnap called for philosophers to use the much more modest claims of confirmation. Carnap also insisted that the criterion of scientific admissibility be applied basic term by basic term.  That is, Carnap analyzes each part of a sentence to determine if it can be connected to empirical claims about the world. By analyzing each component part, Carnap is able to keep nonsense metaphysics out of scientific theories more effectively than Popper and Ayer (who analyze whole propositions at a time), although he has gaps of his own. http://www.phil.cmu.edu/projects/carnap/CWRC_main.htm Carnap’s criterion is part of a long term project. He aims to construct a logical language that can aptly serve as foundation to the empirical sciences. His program is about clarifying debates within science so as to eliminate needless disputes (like the ID-evolution debate), and to allow for more clarity in seeing explanatory pathways. Like scientific theories, no demarcation criterion will ever be perfect: they all restrict too little in some areas, and too much in others. Compared with Popper and Ayer, Carnap’s program of confirmation seems to best support the claims of biology. Regardless of one’s choice, it’s important to know that there are viable alternatives to philosophically define science. Further Reading: On Verifiability: Alfred Jules Ayer, Language, Truth and Logic. On Falsifiability: Karl Popper, The Logic of Scientific Discovery. On Confirmability: Rudolf Carnap, Introduction to the Philosophy of Science, “Testability and Meaning”, and The Logical Syntax of Language. Acknowledgements: Research for this project was directed by Dr. Richard Creath, Professor of Philosophy. Dr. Creath and Matt Chew advised on creating the poster. This research was supported in part by funds from the ASU Office of the Provost through the School of Life Sciences Enrichment Programs. [1] Dembski, William. http://www.designinference.com/documents/2004.04.Five_Questions_Ev.pdf