Over the centuries since the modern scientific revolution that started with Copernicus, Galileo, Kepler, and Newton, two things have changed that have required reorientation of our assumptions and re-education of our reflexes. First, we have learned that even the very best science is fallible; eminently successful theories investigated and supported through the best methods, and by the best evidence available, might be not just incomplete but wrong. That is, it is possible to have a justified belief that is false. (...) Second, we have learned that it is impossible, even for scientists, to maintain the Enlightenment ideal of “thinking for oneself” on every matter about which we want to have, and do think we have, knowledge; the volume of information involved makes us all epistemically dependent on others. (Kant 1996) Scientists in practice have adjusted to these developments much more easily than have lay people. It is also easier to adjust in scientific practice than it is to explain these matters explicitly and accurately to others. To do so it is helpful to consider our epistemological situation precisely, and to understand the broader cultural ideas and historical forces at work in modern science and its public reception. (shrink)
Over the centuries since the modern scientific revolution that started with Copernicus, Galileo, Kepler, and Newton, two things have changed that have required reorientation of our assumptions and re-education of our reflexes. First, we have learned that even the very best science is fallible; eminently successful theories investigated and supported through the best methods, and by the best evidence available, might be not just incomplete but wrong. That is, it is possible to have a justified belief that is false.
From the mid-1980‘s to the early 2000‘s the wide-ranging resources of the concept we now call sensitivity , which Robert Nozick used to give an analysis of the concepts of knowledge and evidence , went largely unappreciated in epistemology. This was in part because these resources were upstaged by a glamorous implication the condition has for skepticism, and in part because of loss of faith in the project of giving a theory of knowledge at all, due to the failure time (...) and again to construct a theory without counterexamples. The sensitivity condition, or as Nozick called it the variation condition, which requires that were p to be false you wouldn‘t believe it, had its own apparent counterexamples. And while the implication of this condition for skepticism was elegant and principled – it is possible to know that there is a table in front of you without knowing you are not a brain in a vat – it had the price of denying closure of knowledge under known implication, that is, denying that knowing q and knowing that q implies p are together sufficient to make the belief in p that you have on that basis knowledge. (shrink)
Less discussed than Hume’s skepticism about what grounds there could be for projecting empirical hypotheses is his concern with a skeptical regress that he thought threatened to extinguish any belief when we reflect that our reasoning is not perfect. The root of the problem is the fact that a reflection about our reasoning is itself a piece of reasoning. If each reflection is negative and undermining, does that not give us a diminution of our original belief to nothing? (...) It requires much attention to detail, we argue, to determine whether or not there is a skeptical problem in this neighborhood. Consider that if we subsequently doubt a doubt we had about our reasoning, that would suggest a restoration of some of the force of our original belief. We would then have instead of runaway skepticism an alternating sequence of pieces of skeptical reasoning that cancel each others’ effects on our justification in the original proposition, at least to some degree. We will argue that the outcome of the sequence of reflections Hume is imagining depends on information about a given case that is not known a priori. We conclude this from the fact that under three precise, explanatory, and viable contemporary reconstructions of what this kind of reasoning about reasoning could be like and how it has the potential to affect our original beliefs, a belief-extinguishing regress is not automatic or necessary. (shrink)
Nancy is ultimately most concerned about how to determine the relevance of evidence to implementation of evidence-based policy guidelines, in other words, the transferability of study results to a population different from the one that was studied and in which procedures or conditions are not the same as those in the study. And she is concerned about the privileged position Randomized Controlled Trials (RCTs) are given in the ranking schemes for evidence-based policy, because as she sees it RCTs do not (...) address this question while other methods do. RCTs are highly regarded because of their strength in ruling out confounding variables, but they can be weak on the transferability problem because the manipulations necessary for controlled experiment also guarantee that the setting and population are different from the situation and population targeted for application. However, both of these familiar points are simplifications that can be misleading. Some non-RCT type studies (e.g. soft interventions) can also be very good at ruling out confounding variables.1 And, as I will explain, the problems leading to the transferability problem – interacting variables and a difference between study and target populations – are present in any study, not unique to RCTs. In addition. (shrink)
The late Berkeley philosopher Paul Feyerabend took perhaps the most permissive attitude possible towards “fringe” or “marginal” science. This flowed from a more general view about how science works best in promoting both knowledge and happiness. He argued that in order to maximize the empirical testability of our theories – a goal even a falsificationist like Karl Popper should love – we must compare them not just to observations, but to other incompatible, even apparently falsified, theories. Methodologically, this is clearly (...) sound, since which observations we make and how we construe them are affected by the ideas we use and the concepts we consider. We often have to consider contrasting ideas in order to find the observations that show the weaknesses of those ideas we already have. Further, Feyerabend saw that if testability alone is the goal of science, then there is no principled way to limit the ideas and theories that ought at any time to be given an audience. The oldest, the kookiest, the most disreputable ideas have a necessary role to play. Like John Stuart Mill he thought that one of the benefits of a truly free marketplace of ideas was that it would allow advocacy of unpopular views as well as respected ones, so that the ugly ducklings could keep the respected ideas honest, and stay alive for the day when they might show the insight they can bring. One could think of the pursuit of truth along these lines as an investigation of an elephant by several people with blindfolds on, each of whom has access only to his own portion of the animal. One would think it was a tree trunk, another a fire hose, a third maybe a whip, another an outsized yoga ball. None of these claims would be right, but if one of these people were too eager and insistent in drawing conclusions and didn’t listen to the very different and seemingly crazy ideas of the others, he might never think of observing beyond his region of the elephant. He would also, Feyerabend thought, lead a cramped and unfulfilled life. An obvious objection to this outlook is that we don’t have the resources to water a thousand flowers.. (shrink)
It is widely accepted that in fallible reasoning potential error necessarily increases with every additional step, whether inferences or premises, because it grows in the same way that the probability of a lengthening conjunction shrinks. As it stands, this is disappointing but, I will argue, not out of keeping with our experience. However, consulting an expert, proof-checking, constructing gap-free proofs, and gathering more evidence for a given conclusion also add more steps, and we think these actions have the potential to (...) improve our reliability or justifiedness. Thus, the received wisdom about the growth of error implies a skepticism about the possibility of improving our reliability and level of justification through effort. Paradoxically, and even more implausibly, taking steps to decrease your potential error necessarily increases it. I will argue that the self-help steps listed here are of a distinctive type, involving composition rather than conjunction. Error grows differently over composition than over conjunction, I argue, and this dissolves the apparent paradox. (shrink)
It is received wisdom that the skeptic has a devastating line of argument in the following. You probably think, he says, that you know that you have hands. But if you knew that you had hands, then you would also know that you were not a brain in a vat, a brain suspended in fluid with electrodes feeding you perfectly coordinated impressions that are generated by a supercomputer, of a world that looks and moves just like this one. You would (...) know you weren’t in this state if you knew you had hands, since having hands implies you are no brain in a vat. You obviously don’t know you’re not a brain in a vat, though—you have no evidence that would distinguish that state from the normal one you think you’re in. Therefore, by modus tollens, you don’t know you have hands. At least, the skeptic has a devastating argument, it is thought, if we grant him closure of knowledge under known implication, which many of us are inclined to do: roughly, if you know p, and you know that p implies q, then you know q.i To say that this is an intuitively compelling argument is an understatement; the project of finding a reply that isn’t table-thumping, or obfuscating, or special-pleading has exercised philosophers for a very long time. The steps of the argument have been scoured in detail to try to find cracks that will yield under pressure. Some of these efforts have been intriguing, and illuminating, and some even appear to provide dialectical victories that shift the burden of proof back to the skeptic. However, as refutations they all come up short. I will argue that we have missed a very simple point: though the skeptical argument above is valid, it has a false premise, namely, the claim that the thing we obviously know implies the thing we seem obviously not to know. This premise, I will argue, cannot be repaired, so we have a refutation; if the skeptic wants to convince us to worry about our ordinary knowledge, he will have to come up with a completely different argument. Closure of knowledge under known implication (hereafter “closure”), is obviously necessary for the skeptical argument presented above.. (shrink)
It is received wisdom that the skeptic has a devastating line of argument in the following. You probably think, he says, that you know that you have hands. But if you knew that you had hands, then you would also know that you were not a brain in a vat, a brain suspended in fluid with electrodes feeding you perfectly coordinated impressions that are generated by a supercomputer, of a world that looks and moves just like this one. You would (...) know you weren’t in this state if you knew you had hands, since having hands implies you are no brain in a vat. You obviously don’t know you’re not a brain in a vat, though—you have no evidence that would distinguish that state from the normal one you think you’re in. Therefore, by modus tollens, you don’t know you have hands. At least, the skeptic has a devastating argument, it is thought, if we grant him closure of knowledge under known implication, which many of us are inclined to do: roughly, if you know p, and you know that p implies q, then you know q. (shrink)
How confident does the history of science allow us to be about our current well-tested scientific theories, and why? The scientific realist thinks we are well within our rights to believe our best-tested theories, or some aspects of them, are approximately true.2 Ambitious arguments have been made to this effect, such as that over historical time our scientific theories are converging to the truth, that the retention of concepts and claims is evidence for this, and that there can be no (...) other serious explanation of the success of science than that its theories are approximately true. There is appeal in each of these ideas, but making such strong claims has tended to be hazardous, leaving us open to charges that many typical episodes in the history of science just do not fit the model. (See, e.g., Laudan 1981.) Arguing for a realist attitude via general claims – properties ascribed to sets of theories, trends we see in progressions of theories, and claimed links between general properties like success and truth that apply or fail to apply to any theory regardless of its content – is like arguing for or via a theory of science, which brings with it the obligation to defend that theory. I think a realist attitude toward particular scientific theories for which we have evidence can be maintained rationally without such a theory, even in the face of the pessimistic induction over the history of science. The starting point at which questions arise as to what we have a right to believe about our theories is one where we have theories and evidence for them, and we are involved in the activity of apportioning our belief in each particular theory or hypothesis in accord with the strength of the particular evidence.3 The devil’s advocate sees our innocence and tries his best to sow seeds of doubt. If our starting point is as I say, though, the innocent believer in particular theories does not have to play offense and propose sweeping views about science in general, but only to respond to the skeptic’s challenges; the burden of initial argument is on the skeptic.. (shrink)
Abstract: Knowledge requires more than mere true belief, and we also tend to think it is more valuable. I explain the added value that knowledge contributes if its extra ingredient beyond true belief is tracking . I show that the tracking conditions are the unique conditions on knowledge that achieve for those who fulfill them a strict Nash Equilibrium and an Evolutionarily Stable Strategy in what I call the True Belief Game. The added value of these properties, intuitively, includes preparedness (...) and an expectation of survival advantage. On this view knowledge is valuable not because knowledge persists but because it makes the bearer more likely to maintain an appropriate belief state—possibly nonbelief—through time and changing circumstances. When Socrates concluded that knowledge of the road to Larissa was no more valuable than true belief for the purpose of getting to Larissa, he did not take into account that one might want to be prepared for a possible meeting with a misleading sophist along the way, or for the possibility of road work. (shrink)
In Tracking Truth I undertook a broader project than is typical today toward questions about knowledge, evidence, and scientific realism. The range of knowledge phenomena is much wider than the kind of homely examples—such as ‘‘She has a bee in her bonnet’’—that are often the fare in discussions of knowledge. Scientists have knowledge gained in sophisticated and deliberate ways, and non-human animals have reflexive and rudimentary epistemic achievements that we can easily slip into calling ‘‘knowledge.’’ What is it about knowledge (...) that makes it natural for us to use the same word in cases that are so vastly different? How is it possible for knowledge to have evolved? What is it about knowledge that it should enhance our power over nature, as Francis Bacon observed? What is it about evidence and knowledge that makes you more likely to have the latter when you have the former? Specialization is necessary to progress, but the division of labor it requires has allowed such questions to fall through the gaps between discussions. These gaps are opportunities. Sometimes newly discovered problems can bring new and better answers even to old questions. The questions I have asked above are ‘‘Why?’’ questions expressed as (apparently) Socratic ‘‘What is?’’ questions, and that is the approach taken in the first five chapters of this book, to offer explanations of familiar phenomena on the basis of rigorous definitions of knowledge and evidence. One might object that this is an old, not a new, style of answer, and one that I ought to be educated enough to reject. Many have thought the project of giving necessary and sufficient conditions for knowledge was in its death rattle long ago. The most common argument for this conclusion is an empirical one, that no such attempt has ever been successful in giving the right answer for all examples. And when one asks, as one must, what the ‘‘right’’ answer would be answering to anyway, the project can look even more depressing. But even if there is a clear.... (shrink)
Reply to Goldman I would like to thank Alvin for a spirited, and gentlemanly, debate we’ve had on these issues, which is extended further here. Alvin is exactly right that if we make his assumption about maximum specificity and deduceability (which I have doubts about), then on my view of knowledge Sphere Guy doesn’t know there’s a sphere in front of him. This may sound silly when we focus on his tactile access to the sphere in the actual world, but (...) if we take a broader view we see that there is more at stake than this. Contrary to Alvin’s impression, methods are not at all excised from my view of knowledge. My theory of how to judge whether someone knows requires us to consider everything (probable) that is and would be responsible for the fact that the person believes or not, whether these occur in his head or in the world, which the formulation in terms of probability helps to make very clear. (See Chapter 3.) Ironically, my refusal to relativize to method has us taking into consideration more facts about the subject’s method than Alvin’s criteria do, for my view takes into account, as appropriate, what process the person would have used and has a tendency to use, and not just the properties of the one he happened in fact to use. When the fact that a method was used by a subject in coming to belief in p is independent of the truth of p, which is actually most of the time in our lives, the conditions of application of the variation condition insure that we evaluate the subject by considering only what he would do and how he would fare in his beliefs were he to use that method he actually used. So, under that condition, my view agrees with Alvin, and Nozick also. But when whether a subject used that method is not independent of the truth value of p, then the variation condition in my view says we must consider in addition the subject’s resulting beliefs in all probable scenarios where he is such that he might well.. (shrink)
The transferability problem—whether the results of an experiment will transfer to a treatment population—affects not only Randomized Controlled Trials but any type of study. The problem for any given type of study can also, potentially, be addressed to some degree through many different types of study. The transferability problem for a given RCT can be investigated further through another RCT, but the variables to use in the further experiment must be discovered. This suggests we could do better on the epistemological (...) problem of transferability by promoting, in the repeated process of formulating public health guidelines, feedback loops of information from the implementation setting back to researchers who are defining new studies. (shrink)
I develop a general framework with a rationality constraint that shows how coherently to represent and deal with second-order information about one's own judgmental reliability. It is a rejection of and generalization away from the typical Bayesian requirements of unconditional judgmental self-respect and perfect knowledge of one's own beliefs, and is defended by appeal to the Principal Principle. This yields consequences about maintaining unity of the self, about symmetries and asymmetries between the first- and third-person, and a principled way of (...) knowing when to stop second-guessing oneself. Peer disagreement is treated as a special case where one doubts oneself because of news that an intellectual equal disagrees. This framework, and variants of it, imply that the typically stated belief that an equally reliably peer disagrees is incoherent, and thus that pure rationality constraints without further substantive information cannot give an answer as to what to do. The framework also shows that treating both ourselves and others as thermometers in the disagreement situation does not imply the Equal Weight view. (shrink)
Sherrilyn Roush defends a new theory of knowledge and evidence, based on the idea of "tracking" the truth, as the best approach to a wide range of questions about knowledge-related phenomena. The theory explains, for example, why scepticism is frustrating, why knowledge is power, and why better evidence makes you more likely to have knowledge. Tracking Truth provides a unification of the concepts of knowledge and evidence, and argues against traditional epistemological realist and anti-realist positions about scientific theories and for (...) a piecemeal approach based on a criterion of evidence, a position Roush calls "real anti-realism." Epistemologists and philosophers of science will recognize this as a significant original contribution. (shrink)
On analogy with testimony, I define a notion of a scientific theory’s lacking or having candor, in a testing situation, according to whether the theory under test is probabilistically relevant to the processes in the test procedures, and thereby to the reliability of test outcomes. I argue that this property identifies what is distinctive about those theories that Karl Popper denounced as exhibiting “reinforced dogmatism” through their self-protective behavior (e.g., psychoanalysis, Hegelianism, Marxism). I explore whether lack of candor interferes with (...) the testing of theories, and conclude that (1) our default attitude toward theories that lack candor in a given test should be suspicion, but (2) the circumstance that a theory lacks candor in a testing situation does not preclude obtaining independent evidence for the auxiliary assumptions to which the theory is probabilistically relevant, and thereby eliminating the problem that lack of candor creates. Thus, Popper was right to think that lack of candor is a bad thing, but wrong to conclude that candor is a criterion of the scientificity of a theory. Seeing this requires recognition of some differences between intuitive relevance and probabilistic relevance, and proper appreciation of the notion of screening off and of the fact that probabilistic relevance is not transitive. (shrink)
This paper addresses two examples due to Peter Achinstein purporting to show that the positive relevance view of evidence is too strong, that is, that evidence need not raise the probability of what it is evidence for. The first example can work only if it makes a false assumption. The second example fails because what Achinstein claims is evidence is redundant with information we already have. Without these examples Achinstein is left without motivation for his account of evidence, which uses (...) the concept of explanation in addition to that of probability. (shrink)
Physicist J. Richard Gott uses the Copernican principle that “we are not special” to make predictions about the future lifetime of the human race, based on how long the human race has been in existence so far. We show that the predictions which can be derived from Gott’s argument are less strong than one might be inclined to believe, that Gott’s argument illegitimately assumes that the human race will not last forever, that certain versions of Gott’s argument are incompatible with (...) Bayesian conditionalization, and that Gott’s argument is self-refuting. (shrink)