Introduction:the nature of science 5 could come into being and replicate.Nonetheless,a scientist's rational adherence to a theory does not require it to be flawless,let alone be without a problem.Scientists require a theory to be a good,preferably the best available,explanation of a range of important phenomena.This in turn depends on the theory's ability to generate and maintain strategies for solving problems. So the sign of a successful theory is not the absence of problems but its ability to solve those problems which do arise.An instance of this is explained by Stephen Jay Gould in his famous essay The panda's thumb.The giant panda appears to have six fingers,one of which is an opposable thumb useful for gripping things such as bamboo stalks.This is very odd.Primates,but few other animals,have an opposable thumb.According to the story of primate evolution this is a development of one of five digits.Bears have the same five digits but have not developed any of them into a thumb,because their paws have evolved,like those of many animals,for the purpose of running.Where does the panda's thumb come from?Being a sixth finger it cannot have developed from one of the preexisting five,as in the case of the human thumb.But the evolution of a completely new finger,though perhaps possible,seems unlikely.(Perhaps one might wonder if the panda did not evolve but was put on Earth properly designed for its purpose.)It turns out that the panda's thumb is not a true finger at all.There are no new bones involved.Rather an existing bone,part of the panda's wrist,has become elongated until it is able to function like an opposable thumb.Evolutionarily this is highly plausible.Gould's point is that nature does not show evidence of design but the adaptation for a new purpose of organs and limbs that first evolved with a different purpose (which he says is more like tinkering than design).My point,more broadly,is that the ability of evolutionary theory to cope with such oddities is the reason why scientists find it credible.As long as it continues to be successful in this way the appearance of new problems,far from being a sign of failure,is what provides fuel for growing knowledge.Of course it may be that the problems begin to pile up without the recompense of adequate solutions,and then we may be in a different ballpark.This is an interesting issue and we shall come back to it later in this book. Judge Overton's reasons for rejecting creation "science"are useful to us not only in providing criteria for deciding what may or may not properly be called science,but also because they highlight many of the ideas and notions that we as philosophers of science must investigate.His analysis says that science should concern natural laws or explanations in terms of natural law.But what is a natural law and what counts as an explanation?While these concepts may have been clear enough for the judge's purposes, we shall see that once one looks at them at all closely all sorts of problems begin to arise. A claim of the creationists which the court rejected was that living things come in distinct kinds.The judge and the witnesses against the State of Arkansas seemed to think that this concept is unscientific.Perhaps one can see why,given the creationists'use of it. In their view,mankind belongs to a different kind from other primates.Yet they also claim that all the different species of bats (over 800 of them forming a diverse order) belong to a single kind.This seems an odd and tendentious notion of kind.But surely there is some sense in saying that chemical elements make up distinct kinds?And what about different species?We shall see whether there is a need for a notion of natural kind and what that notion is.could come into being and replicate. Nonetheless, a scientist’s rational adherence to a theory does not require it to be flawless, let alone be without a problem. Scientists require a theory to be a good, preferably the best available, explanation of a range of important phenomena. This in turn depends on the theory’s ability to generate and maintain strategies for solving problems. So the sign of a successful theory is not the absence of problems but its ability to solve those problems which do arise. An instance of this is explained by Stephen Jay Gould in his famous essay The panda’s thumb. The giant panda appears to have six fingers, one of which is an opposable thumb useful for gripping things such as bamboo stalks. This is very odd. Primates, but few other animals, have an opposable thumb. According to the story of primate evolution this is a development of one of five digits. Bears have the same five digits but have not developed any of them into a thumb, because their paws have evolved, like those of many animals, for the purpose of running. Where does the panda’s thumb come from? Being a sixth finger it cannot have developed from one of the preexisting five, as in the case of the human thumb. But the evolution of a completely new finger, though perhaps possible, seems unlikely. (Perhaps one might wonder if the panda did not evolve but was put on Earth properly designed for its purpose.) It turns out that the panda’s thumb is not a true finger at all. There are no new bones involved. Rather an existing bone, part of the panda’s wrist, has become elongated until it is able to function like an opposable thumb. Evolutionarily this is highly plausible. Gould’s point is that nature does not show evidence of design but the adaptation for a new purpose of organs and limbs that first evolved with a different purpose (which he says is more like tinkering than design). My point, more broadly, is that the ability of evolutionary theory to cope with such oddities is the reason why scientists find it credible. As long as it continues to be successful in this way the appearance of new problems, far from being a sign of failure, is what provides fuel for growing knowledge. Of course it may be that the problems begin to pile up without the recompense of adequate solutions, and then we may be in a different ballpark. This is an interesting issue and we shall come back to it later in this book. Judge Overton’s reasons for rejecting creation “science” are useful to us not only in providing criteria for deciding what may or may not properly be called science, but also because they highlight many of the ideas and notions that we as philosophers of science must investigate. His analysis says that science should concern natural laws or explanations in terms of natural law. But what is a natural law and what counts as an explanation? While these concepts may have been clear enough for the judge’s purposes, we shall see that once one looks at them at all closely all sorts of problems begin to arise. A claim of the creationists which the court rejected was that living things come in distinct kinds. The judge and the witnesses against the State of Arkansas seemed to think that this concept is unscientific. Perhaps one can see why, given the creationists’ use of it. In their view, mankind belongs to a different kind from other primates. Yet they also claim that all the different species of bats (over 800 of them forming a diverse order) belong to a single kind. This seems an odd and tendentious notion of kind. But surely there is some sense in saying that chemical elements make up distinct kinds? And what about different species? We shall see whether there is a need for a notion of natural kind and what that notion is. Introduction: the nature of science 5