The Theory of Evolution Cannot Explain All Organisms.

<<< REBUTTAL AGAINST PRO >>> In the previous round, I provided an explanation of how evolution could lead to the development of an irreducibly complex system. The process I described – using accepted evolutionary principles – involved a system with three components that gradually evolved and co-adapted, thereby becoming better at performing one particular function together, while losing their ability to perform their previous individual functions. This evolved system was irreducibly complex, because when one component was removed, none of the remaining parts could function. The purpose of this exercise was to demonstrate that irreducibility is not a challenge to evolutionary theory. In response, my opponent has provided no arguments against the principles of evolution that I employed in my discussion. Instead, my opponent claims this process – as it relates to structures we observe in nature – is unlikely because: (1) the functions performed by the individual parts of the system in the past are speculative; (2) the parts “fit together” too well to have evolved to work together; and (3) the assembly of complex systems is too complicated to have evolved. Only the second objection actually relates to the principles of evolution, and that objection fails to address why evolution could not lead to parts that “fit together” well. Instead, my opponent’s objections express a general disbelief that these systems could have been the result of evolution and must therefore have been designed – which, unfortunately, is not a tenable argument. For clarification, I will rebut each of my opponent’s objections in more detail. 1. Rebuttal to :: The previous functions of the individual parts of the system are speculative and therefore evolution is not a sufficient explanation for these systems My opponent’s first objection is that the previous functions performed by the individual parts of a complex system are speculative, and therefore how can we know they evolved? Unfortunately, my opponent is applying a misleading bait-and-switch. He is attempting to shift the burden of proof from providing plausible evolutionary pathways to requiring the actual evolutionary story. My opponent is appealing to ignorance – essentially saying, we don’t “this,” therefore it must have been “this other thing.” The process of evolutionary change of individual proteins within systems is well documented.[1][2] The fact that we have not yet described the evolutionary history of every single system is not an argument against evolution. There was a time, for example, when scientists did not know the evolutionary history of the vertebrate blood clotting system, a complex system composed of more than two dozen separate proteins. Today, the evolutionary development of this complex clotting system is well known.[3][4] The absence of factual knowledge is not an argument against evolution or its well-documented validity. 2. Rebuttal to :: Evolution of complex systems could not occur because the parts of these systems fit together too well Second, my opponent claims that the evolution of complex systems could not occur because the individual components of these systems “fit together” too well to have evolved. He states “each protein is like a key that fits into a lock.” My opponent is correct that many proteins have a lock-and-key relationship with other proteins and molecules – this is well documented in the scientific literature.[5] But, this relationship can and has been explained by evolutionary theory. Imagine that you have two proteins that loosely interact. Now, imagine that cells that have tighter interactions between these two proteins will survive better – for example, perhaps these proteins are cooperative enzymes and a tighter interaction allows for more efficient use of necessary nutrients. Suddenly, evolution is selecting for variations of these two proteins that will have tighter interactions. Eventually, what was once a loose interaction becomes a tight interaction. This is not hypothetical, the evolutionary history of many such relationships is known, including how they came into existence through evolutionary change. One prominent example is the integrated molecular system of aldosterone and its receptor protein.[5] My opponent’s argument is not a challenge to evolutionary theory and has been predicted, observed, and explained within evolutionary frameworks. 3. Rebuttal to :: Complex systems are too complicated to have evolved Finally, my opponent asserts that the assembly of complex systems is too complicated to have evolved. He points to the flagella and its many parts, and appeals to that complexity as though it refutes evolution. He provides no evidence that evolution could not lead to complex systems, other than his personal disbelief. This is an argument from incredulity. The fact that the flagellum and other systems are complex and difficult to understand does not indicate it was designed and provides no evidence to believe it was designed. Moreover, evolution predicts that complex systems will evolve over time. Scientists have already demonstrated that huge varieties of complex systems can be created by evolutionary forces.[6] And, by way of example, I already noted two complex system that have been explained in great detail by evolution – for example, the vertebrate clotting system, composed of over two dozen different proteins, is highly complex and yet has been explained in evolutionary terms. Complexity is not an argument against evolution. <<< CONCLUSION >>> My opponent points to the complexity of molecular systems and essentially argues that it is improbable that these systems could have evolved. He does not provide actual evidence of improbability, only that he does not believe so many pieces could have evolved to work together in this way – despite that current scientific understanding provides the evolutionary principles necessary to understand how these systems can and do develop. My opponent also misleadingly points to the complex systems that science has not yet fully described. In essence, he says “science has not yet explained the evolution of this system, therefore it must be design.” He ignores, however, the many other systems that science has described in evolutionary terms. This is a “god in the gaps” appeal, an attempt to support intelligent design simply by pointing to areas in which science has not yet provided a detailed understanding. There is no reason to accept this argument, because it is not an argument at all. I have shown that evolutionary theory explains and predicts the development and existence of complex, irreducible systems. My opponent has not, in any way, rebuffed these claims. Moreover, I remind you that it is my opponent’s burden to disprove the adequacy of evolution theory, which he has failed to do. SOURCES [1] http://www.plosbiology.org... [2] http://www.plosgenetics.org... [3] Russell Doolittle, The Evolution of Vertebrate Blood Clotting (2012). [4] http://www.ncbi.nlm.nih.gov... [5] http://www.ncbi.nlm.nih.gov... [6] http://www.nature.com...