This article is available at1http://www.nhm.org/research/annelida/Mechanics_of_Testing.htmemail: [email protected] MECHANICS OF TESTING A THEORY: IMPLICATIONS FORINTELLIGENT DESIGN1J. Kirk Fitzhugh, Ph.D.2Research & CollectionsNatural History Museum of Los Angeles County-2-INTRODUCTIONIn my article, Evolutionary Biology versusIntelligent Design: Resolving the Issue , I3briefly outlined the nature of hypothesesand theories. Hypotheses are explanatoryconstructs, suggesting past causal conditionsthat might account for effects observed in thepresent, while theories are established orgenerally accepted explanatory concepts, orset of concepts, that we apply to our senseperceptions to give us understanding of whatwe do or might perceive. An important aspectstressed in that article is that hypotheses referto specific events in the past and effects in thepresent, whereas theories are spatially andtemporally unconstrained. Theories areintended to apply to the past, present, andfuture; on this planet, in this galaxy, andbeyond.Given the differences between hypothesesand theories, the protocols for criticallyassessing their veracity by way of theprocedure of testing also show distinctdifferences. The most obvious is that thetesting of theories has the quality of anexperiment, where one must be in a situationto witness the causal conditions stipulated bythe theory, as well as subsequently observingthe effect(s) from those conditions. As willbe discussed next, it is this experimentalcharacter that imposes distinct limitations onwhat theories can be critically evaluated in therealm of science, providing the criterion fordemarcating the theories comprisingevolutionary biology from any theory of‘intelligent design’ (ID). The principleimplication to be identified is that any IDtheory is immune to testing. A relatedimplication is that a hypothesis derived froman ID theory, especially pertaining toorganisms, also exhibits this quality ofimmunity. As the goal in any field of scienceis the ever-increasing acquisition of causalunderstanding, ID cannot be subjected to thecritical testing that is consistent with thatgoal.THE STRUCTURE OF THEORY TESTSI noted earlier that the testing of a theoryrequires that one be in a position to knowand/or observe the causal conditions underwhich a particular theory is claimed toprovide understanding. The act of testingdetermines whether or not the causal relationsstated in a theory manifest themselves.The basic format of any theory, as ageneral statement of cause and effectrelations, has the following form:[1] Theory á: When causal conditions oftype x occur, effects of type y will occur.Developing a test of theory á would involvethe derivation of specific predicted effectsthat should follow from the stated causalconditions. The basic format of a potentialtest of theory á would then have the form:[2] Potential test of theory á: If the causal1conditions of type x are encountered, then1an effect of type y should then beobserved.The actual test of theory á would thenhave the form of an experiment, be it underlaboratory or natural conditions, during which1causal conditions of type x are produced, andeffects subsequently observed. If effects areas one predicted, then the effects provideconfirming evidence for the theory, giving onereason to conclude that the theory has, at leastfor the moment, some worth as a tool foracquiring understanding. Such a test would Available at 3http://www.nhm.org/research/annelida/eb_vs_id.html-3-have the form:a[3] Actual test of theory á (instance ofconfirmation): A causal condition of10type x was created in the lab at time t ,11and an effect of type y was observed at t . Theory á is currently accepted as aconstruct for providing causalunderstanding.Alternatively, if the effects that follow1from the known causal conditions of type xare not those predicted by the theory, then thisis potential evidence disconfirming the theory:b[4] Actual test of theory á (instance ofdisconfirmation): A causal condition of10type x was created in the lab at time t ,21and an effect of type y was observed at t . Theory á does not appear to providerelevant causal understanding, potentiallyleaving consideration of other theories, orrevision of theory á.In other words, the cause and effect relationsclaimed by the theory do not appear to hold.The theory might either be in jeopardy and inneed of being replaced, or it might simplyrequire revision to some extent.IMPLICATIONS FOR INTELLIGENT DESIGNTHEOR IESGiven the mechanics required for testingtheories, what are the implications forcritically evaluating any ID theory? The mostserious impediment to testing an ID theory isthe simple realization that it would never bepossible to empirically witness the actions ofan intelligent agent as part of the conditionsrequired in the act of testing, such that onecould ascertain if the causal relations stated inthe theory actually manifest themselves. If anintelligent agent cannot be discerned, then anyID theory is immediately immune to beingtested, contrary to the test conditionsstipulated in [3] and [4]. As a consequence,there could be no observed effects that couldserve as confirming evidence for an ID theory.By the same token, it would not be possible toclaim any ID theory to be disconfirmed by anyobserved effects. As an intelligent agentcannot be witnessed during some set of testconditions, that agent could not be ruled outas having some part to play in the conditionsthat are witnessed. Recall once again thattheories assert cause and effect relations, e.g.,[1]. The goal of testing is to evaluate theveracity of the claim of such relations. Thisrequires that causal agents, conditions, and/orevents be available to observation. If suchagents, conditions, and events cannot even beintroduced into the realm of testing a giventheory, then it is not at all possible to subjectthat theory to testing.Let’s look at an actual example of thedifficulty of testing an ID theory. In his book,Darwin’s Black Box, Behe (1996, Free Press,New York) introduced the notion of‘irreducible complexity.’ Irreduciblecomplexity is the view that some biologicalstructures are too complex to have beendeveloped naturally through the processes ofrandom mutations and natural selection.Additionally, there is the contention that sincesuch complex structures cannot function ifcritical components are missing, then naturalselection could not have operated