Rejoinder: Think Theory Testing, Not Realism

Eric Tsang's response makes the legitimate point that prediction and explanation can be different goals. However, his arguments also suffer from several errors in logic, most often the converse error. I do not claim that unrealistic assumptions breed good theories. I only claim that breakthrough theories usually have assumptions deemed unrealistic. Hence, unrealistic assumptions breed both good and bad theories. That is why science tests theories, not assumptions. Moreover, one can easily prove that realistic assumptions are not required. Consider situations when one of two competing theories must be correct. For example, in criminal cases, the prosecution's theory is that the accused committed the crime. The defense's theory is that the accused is innocent. One theory is correct despite the fact that both could make obviously unrealistic assumptions. For example, the prosecution might unrealistically assume that unreliable eyewitness testimony is sufficient to convict. The defense might unrealistically assume that a dubious alibi is sufficient to acquit. Juries decide on all the evidence and not each assumption. I now answer some of Eric Tsang's questions.