Scientific theories should require the ability to be falsified.

Con has in effect concededMy opponent has forfeited Round 3. In Round 2 he failed to address my Round 1 arguments, and of course by forfeiting he did respond to my Round 2 rebuttals. His opportunity to respond is now lost. The debate rules agreed to by my opponent in accepting the challenge include:DR 4. No new arguments shall be made in Round 4. Pro may rebut previous arguments using new evidence solely for that purpose, but no new arguments are allowed. Con may not present any new evidence or make new arguments in R4. R4 is for summarizing the debate and pointing out merits and deficiencies of the arguments rather than introducing new contentions.I think this means Con has conceded the debate.Summary of the debate.My arguments in favor of having a criteria of falsifiability for a scientific theory are that without the possibility of falsification, a scientific theory can neither provide predictions or explanations. A theory that does not face falsification cannot make predictions, because any prediction faces the possibility of falsification. A theory that cannot be falsified does not explain anything, because all outcomes are consistent with the theory, and an explanation must say why some outcomes occur and others do not. without either prediction or explanation, a theory is outside of the realm of science. We agreed at the outset that science was "knowledge about or study of the natural world based on facts learned through experiments and observation." Things outside of science may, for example, be inspirational, artistic, or poetic; but without prediction or explanation of the natural world, they are not part of science.Con claimed three examples of valid scientific theories that were not falsifiable. 1. Phlogiston theory is not an example of a valid non-falsifiable scientific theory because it was in fact falsified.2. Lorentz transformations are not an example of a valid non-falsifiable scientific theory because they equate to a case of special relativity, and special relativity is falsifiable.3. Unobservable entities are not counter-examples to non-falsifiability because the scientific theories are not about what the entities are, but rather about how nature behaves. For example, string theory does not claim that there are really tiny strings resonating at the subatomic level. The "strings" are explicitly acknowledged as being useful analogies. The theory gives predictive equations, and stops short of making claims about what the equations literally represent. The same is true of electromagnetic field theory. The theory is given precisely by Maxwell's equations, with the concept of fields an explanatory analogy.I gave examples of examples of non-falsifiable theories: divine plan, astrology, creationism, Freudian psychoanalysis, and Marxism. They are not falsifiable because in each case no test of the theory has been accepted by advocates that would prove it false. None have predictive or explanatory power, so none are part of science. A theory may be true, but still be not part of science.Con pointed to several problems in using falsifiability as a test of a scientific theory. The problems are real, but in no case is the problem resolved by abandoning falsifiability as a criteria for a valid scientific theory.If a test fails, scientists do not immediately know if assumptions embodied in the test in the test were wrong or the theory was wrong. Perhaps the experimental apparatus did not work as expected, rather than the theory not working as expected. The requirement for falsification is not supposed to resolve every problem in science. It only says that there is problem that must be resolved.Con pointed to historical examples of true theories that failed early tests. Further tests showed that the apparent failures of the theory were not the result of valid tests. I cited phlogiston theory, phlebotomy, and the luminiferous ether as examples of theories like that could not be revived after failed experiments. Falsification may not be easy, but the requirement produces sound scientific theories.Indeed, falsification does not demand that a paradigm be immediately abandoned. That's not the point. The point is that scientists must still work to resolve the question of why the test failed.It may be impossible to test a theory for practical reasons, including the case where the prediction is too rare to observe. That situation does not invalidate the principle of falsification. Being untestible as a practical matter renders the theory useless for practical reasons, not because it was required to be falsifiable. Advancing technology, a bigger science budget, or a new approach to verification may take the theory off the shelf for testing. Abandoning falsifiability doesn't make the theory any more useful or give it more explanatory power.There were more arguments, but since Con did not respond I won't repeat my Round 2 presentation. My arguments remain unanswered.---------------------------Con should lose the conduct category for his forfeit.Con should lose for failure to address my affirmative claims that falsifiability is necessary for a scientific theory to be useful and to explain nature, for failure to give a valid example of non-falsifiable theory having scientific validity, and for failure to counter my rebuttals.