Despite their success in describing and predicting cognitive behavior, the plausibility of so-called ‘rational explanations’ is often contested on the grounds of computational intractability. Several cognitive scientists have argued that such intractability is an orthogonal pseudoproblem, however, since rational explanations account for the ‘why’ of cognition but are agnostic about the ‘how’. Their central premise is that humans do not actually perform the rational calculations posited by their models, but only act as if they do. Whether or not (...) the problem of intractability is solved by recourse to ‘as if’ explanations critically depends, inter alia, on the semantics of the ‘as if’ connective. We examine the five most sensible explications in the literature, and conclude that none of them circumvents the problem. As a result, rational ‘as if’ explanations must obey the minimal computational constraint of tractability. (shrink)

Many cognitive scientists, having discovered that some computational-level characterization f of a cognitive capacity φ is intractable, invoke heuristics as algorithmic-level explanations of how cognizers compute f. We argue that such explanations are actually dysfunctional, and rebut five possible objections. We then propose computational-level theory revision as a principled and workable alternative.

This paper focuses on the cognitive/computational and evolutionary levels. It describes three proposals to make cognition computationally tractable, namely: Resource Rationality, the Adaptive Toolbox and Massive Modularity. While each of these proposals appeals to evolutionary considerations to dissolve the intractability of cognition, Rich, Blokpoel, de Haan, and van Rooij argue that, in each case, the intractability challenge is not resolved, but just relocated to the level of evolution.

It has been widely recognized since ancient times that a standard way to resolve disagreement is for one party to extract concessions from the other which he or she is less prepared to give up than his original thesis. Central to this methodology is specifying the various forms of consequence which bear on matters already conceded. Not all disagreements are responsive to this methodology. I shall speak of a class of disagreements as intractable when parties are unwilling to “split the (...) difference” or to “agree to disagree” and yet are unable to agree on procedures to resolve their original disagreement.. When intractable disagreements turn on values that are widely held and widely judged to be of the first importance, intractable disagreements constitute an apparent impediment to social policy formation. An urgent question is this: “Is coherent and supportable public policy possible concerning matters subject to intractable disagreement?”. (shrink)

This paper focuses on the cognitive/computational and evolutionary levels. It describes three proposals to make cognition computationally tractable, namely: Resource Rationality, the Adaptive Toolbox and Massive Modularity. While each of these proposals appeals to evolutionary considerations to dissolve the intractability of cognition, Rich, Blokpoel, de Haan, and van Rooij argue that, in each case, the intractability challenge is not resolved, but just relocated to the level of evolution.

Bayesian models are often criticized for postulating computations that are computationally intractable (e.g., NP-hard) and therefore implausibly performed by our resource-bounded minds/brains. Our letter is motivated by the observation that Bayesian modelers have been claiming that they can counter this charge of “intractability” by proposing that Bayesian computations can be tractably approximated. We would like to make the cognitive science community aware of the problematic nature of such claims. We cite mathematical proofs from the computer science literature that show (...) intractable Bayesian computations, such as postulated in existing Bayesian models, cannot be tractably approximated. This does not mean that human brains do not (or cannot) implement the type of algorithms that Bayesian modelers are advancing, but it does mean that proposing that they do by itself does nothing to parry the charge of intractability, because the postulated algorithms are as intractable (i.e., require exponential time) as the computations they try to approximate. Besides our negative message for the community, our letter also makes a positive contribution by referring to a methodology that Bayesian modelers can use to try and parry the charge of intractability in a mathematically sound way. (shrink)

Brain death has been accepted worldwide medically and legally as the biological state of death of the organism. Nevertheless, the literature has described persistent problems with this acceptance ever since brain death was described. Many of these problems are not widely known or properly understood by much of the medical community. Here we aim to clarify these issues, based on the two intractable problems in the brain death debates. First, the metaphysical problem: there is no reason that withstands critical scrutiny (...) to believe that BD is the state of biological death of the human organism. Second, the epistemic problem: there is no way currently to diagnose the state of BD, the irreversible loss of all brain functions, using clinical tests and ancillary tests, given potential confounders to testing. We discuss these problems and their main objections and conclude that these problems are intractable in that there has been no acceptable solution offered other than bare assertions of an ‘operational definition’ of death. We present possible ways to move forward that accept both the metaphysical problem - that BD is not biological death of the human organism - and the epistemic problem - that as currently diagnosed, BD is a devastating neurological state where recovery of sentience is very unlikely, but not a confirmed state of irreversible loss of all [critical] brain functions. We argue that the best solution is to abandon the dead donor rule, thus allowing vital organ donation from patients currently diagnosed as BD, assuming appropriate changes are made to the consent process and to laws about killing. (shrink)

(2013). Intractable Difficulties in Caring for People With Sickle Cell Disease. The American Journal of Bioethics: Vol. 13, No. 4, pp. 22-24. doi: 10.1080/15265161.2013.767959.

It used to be futile to try to save babies born at 23 weeks. It isn’t anymore. It used to be futile to try to keep patients with end-stage congestive heart failure alive. It isn’t anymore. Futility is a moving target. Thus, it is not surprising that doctors, patients, and families often disagree about which treatments are efficacious or futile, appropriate or inappropriate, obligatory or obligatorily withheld. The goalposts keep moving. Yesterday’s impossibility is today’s routine. Why should a patient believe (...) a doctor who says that treatment is futile, inappropriate, or likely to cause more harm than good? Could it just mean that the doctors are unwilling to try everything that is available? When... (shrink)

Both as cardinal and as Pope Benedict XVI, one of Josef Ratzinger's consistent concerns has been the foundational moral imperatives of the natural law. In 2004, then Cardinal Ratzinger requested that the University of Notre Dame study the complex issues embedded in discussions about "natural rights" and "natural law" in the context of Catholic thinking. To that end, Alasdair MacIntyre provided a substantive essay on the foundational problem of moral disagreements concerning natural law, and eight scholars were invited to respond (...) to MacIntyre's essay, either by addressing his work directly or by amplifying his argument along other yet similar paths. The contributors to this volume are theologians, philosophers, civil and canon lawyers, and political scientists, who reflect on these issues from different disciplinary perspectives. Once the contributors' essays were completed, MacIntyre responded with a closing essay. Throughout the book, the contributors ask: Can a persuasive case for a foundational morality be made etsi Deus daretur? And, of course, persuasive to whom? The exchanges that take place between MacIntyre and his interlocutors result, not in answers, but in rigorous attempts at clarification. __Intractable Disputes about the Natural Law__ will interest ethicists, moral theologians, and students and scholars of moral philosophy. "Lawrence Cunningham has assembled an esteemed group of scholars to provide incisive analyses of the contemporary state of natural law theory, particularly in light of Alasdair MacIntyre's groundbreaking work. The essays are lucid, engaging, and intellectually sophisticated. __Intractable Disputes about the Natural Law_ _is a must-read not only for moral theologians, but for anyone concerned about the conceptual foundations of human rights, human dignity, and moral dialogue in pluralistic societies." --_Stephen J. Pope, Boston College_ "MacIntyre's first essay, on its own, would make this book an important scholarly contribution. But the ensuing contributions enable the book to flourish further, with contributions on subjects both readily associated with natural law and moral disagreement as well as those more creatively connected to the genesis of the text. Cunningham's volume both broadens and deepens contemporary thinking on a perennial topic, and will richly reward its readers." --_William C. Mattison III, The Catholic University of America_. (shrink)

Intractability is a growing concern across the cognitive sciences: while many models of cognition can describe and predict human behavior in the lab, it remains unclear how these models can scale to situations of real-world complexity. Cognition and Intractability is the first book to provide an accessible introduction to computational complexity analysis and its application to questions of intractability in cognitive science. Covering both classical and parameterized complexity analysis, it introduces the mathematical concepts and proof techniques that (...) can be used to test one's intuition of tractability. It also describes how these tools can be applied to cognitive modeling to deal with intractability, and its ramifications, in a systematic way. Aimed at students and researchers in philosophy, cognitive neuroscience, psychology, artificial intelligence, and linguistics who want to build a firm understanding of intractability and its implications in their modeling work, it is an ideal resource for teaching or self-study. (shrink)

According to the standard version of discourse ethics (e.g. as formulated by Apel, Habermas, and others), the objectivity of moral norms resides in their intersubjective acceptability under idealized conditions of discourse. These accounts have been criticized for not taking sufficient account of contextual particularities and the realities of actual discourse. This essay addresses such objections by proposing a more realistic, contextualist 'principle of real moral discourse' (RMD). RMD is derived from a more comprehensive concept of objectivity that links intersubjective objectivity (...) with a factual objectivity based in features of social conflicts and the moral problems they pose. To clarify RMD and make this approach more plausible, a number of theoretical and practical questions are addressed concerning the notions of reasonability and inclusivity entailed by RMD. (shrink)

Social epistemologists use the term hermeneutical injustice to refer to a form of epistemic injustice in which a structural prejudice in the economy of collective interpretive resources results in a person’s inability to understand his/her/their own social experience. This essay argues that the phenomenon of unacknowledged date rapes, that is, when a person experiences sexual assault yet does not conceptualize him/her/their self as a rape victim, should be regarded as a form of hermeneutical injustice. The fact that the concept of (...) date rape has been widely used for at least three decades indicates the intractability of hermeneutical injustices of this sort and the challenges with its overcoming. (shrink)

For over a decade, the hypercomputation movement has produced computational models that in theory solve the algorithmically unsolvable, but they are not physically realizable according to currently accepted physical theories. While opponents to the hypercomputation movement provide arguments against the physical realizability of specific models in order to demonstrate this, these arguments lack the generality to be a satisfactory justification against the construction of any information-processing machine that computes beyond the universal Turing machine. To this end, I present a more (...) mathematically concrete challenge to hypercomputability, and will show that one is immediately led into physical impossibilities, thereby demonstrating the infeasibility of hypercomputers more generally. This gives impetus to propose and justify a more plausible starting point for an extension to the classical paradigm that is physically possible, at least in principle. Instead of attempting to rely on infinities such as idealized limits of infinite time or numerical precision, or some other physically unattainable source, one should focus on extending the classical paradigm to better encapsulate modern computational problems that are not well-expressed/modeled by the closed-system paradigm of the Turing machine. I present the first steps toward this goal by considering contemporary computational problems dealing with intractability and issues surrounding cyber-physical systems, and argue that a reasonable extension to the classical paradigm should focus on these issues in order to be practically viable. (shrink)

In The Evolution-Creation Struggle, Michael Ruse seeks to answer, ‘Why is there so much controversy surrounding evolutionary theory?’ He does so by tracing the historical development of the theory and the two major reactions to it. These major reactions, for and against, are not just views about science, but full blooded ‘rival religions.’ They each have a system of origins, morality, and eschatology. So the conflict over evolutionary theory persists because it is a clash between incompatible worldviews. This review praises (...) Ruse’s analysis on a number of points but also argues that he stumbles in three ways. First, he fails to explain that a key aspect of the origins debate concerns disagreement about the definition of science. Second, Ruse improperly uses his own definition of science, with little argument, in order to rule competing views out of science. Third, Ruse misrepresents the epistemology of non-Darwinians as relying on faith, emotion, and mystery instead of evidence and reason. (shrink)

Most people believe that suffering is intrinsically bad. In conjunction with facts about our world and plausible moral principles, this yields a pro tanto obligation to reduce suffering. This is the intuitive starting point for the moral argument in favor of interventions to prevent wild animal suffering. If we accept the moral principle that we ought, pro tanto, to reduce the suffering of all sentient creatures, and we recognize the prevalence of suffering in the wild, then we seem committed to (...) the existence of such a pro tanto obligation. Of course, competing values such as the aesthetic, scientific or moral values of species, biodiversity, naturalness or wildness, might be relevant to the all-things-considered case for or against intervention. Still, many argue that, even if we were to give some weight to such values, no plausible theory could resist the conclusion that WAS is overridingly important. This article is concerned with large-scale interventions to prevent WAS and their tractability and the deep epistemic problem they raise. We concede that suffering gives us a reason to prevent it where it occurs, but we argue that the nature of ecosystems leaves us with no reason to predict that interventions would reduce, rather than exacerbate, suffering. We consider two interventions, based on gene editing technology, proposed as holding promise to prevent WAS; raise epistemic concerns about them; discuss their potential moral costs; and conclude by proposing a way forward: to justify interventions to prevent WAS, we need to develop models that predict the effects of interventions on biodiversity, ecosystem functioning, and animals’ well-being. (shrink)

This chapter explores some fundamental consequences of the correspondence between physical process and computations. Most physical questions may be answerable only through irreducible amounts of computation. Those that concern idealized limits of infinite time, volume, or numerical precision can require arbitrarily long computations, and so be considered formally undecidable. The behavior of a physical system may always be calculated by simulating explicitly each step in its evolution. Much of theoretical physics has, however, been concerned with devising shorter methods of calculation (...) that reproduce the outcome without tracing each step. Computational irreducibility is common among the systems investigated in mathematics and computation theory, but it may well be the exception rather than the rule, since most physical questions may be answerable only through irreducible amounts of computation. (shrink)

The authors put forward an interesting response to detractors of black box algorithms. According to the authors, what is of ethical relevance for medical artificial intelligence is not so much their transparency, but rather their reliability as a process capable of producing accurate and trustworthy results. The implications of this view are twofold. First, it is permissible to implement a black box algorithm in clinical settings, provided the algorithm’s epistemic authority is tempered by physician expertise and consideration of patient autonomy. (...) Second, physicians are not expected to possess exhaustive knowledge or understanding of the algorithmic computation by which they verify or augment their medical opinions. The potential of these algorithms to improve diagnostic and procedural accuracy alongside the quality of patient decision-making is undoubtedly a boon to modern medicine, but blind deference to them is neither feasible nor responsible, as several logistical and ethical quagmires noted by the authors still remain inherent in algorithmic software. I concur …. (shrink)

In this paper we study the semantic data complexity of several controlled fragments of English designed for natural language front-ends to OWL (Web Ontology Language) and description logic ontology-based systems. Controlled languages are fragments of natural languages, obtained by restricting natural language syntax, vocabulary and semantics with the goal of eliminating ambiguity. Semantic complexity arises from the formal logic modelling of meaning in natural language and fragments thereof. It can be characterized as the computational complexity of the reasoning problems associated (...) to their semantic representations. Data complexity (the complexity of answering a question over an ontology, stated in terms of the data items stored therein), in particular, provides a measure of the scalability of controlled languages to ontologies, since tractable data complexity implies scalability of data access. We present maximal tractable controlled languages and minimal intractable controlled languages. (shrink)

Advocates of the computational theory of mind claim that the mind is a computer whose operations can be implemented by various computational systems. According to these philosophers, the mind is multiply realisable because—as they claim—thinking involves the manipulation of syntactically structured mental representations. Since syntactically structured representations can be made of different kinds of material while performing the same calculation, mental processes can also be implemented by different kinds of material. From this perspective, consciousness plays a minor role in mental (...) activity. However, contemporary neuroscience provides experimental evidence suggesting that mental representations necessarily involve consciousness. Consciousness does not only enable individuals to become aware of their own thoughts, it also constantly changes the causal properties of these thoughts. In light of these empirical studies, mental representations appear to be intrinsically dependent on consciousness. This discovery represents an obstacle to any attempt to construct an artificial mind. (shrink)

The basic issue is the measurement of memory accuracy and how correspondence should be assessed. Problems of completeness and variations in the degree and type of inaccuracy make measurement intractably difficult. This difficulty places severe limitations on generalizing across tasks, domains, and individuals and, consequently, on theory construction.

We build on Morgan’s deep conventionalist base by offering a pragmatic approach for achieving normative progress on sports most intractable problems (e.g. performance enhancemen...

In three experiments, we investigated the computational complexity of German reciprocal sentences with different quantificational antecedents. Building upon the tractable cognition thesis (van Rooij, 2008) and its application to the verification of quantifiers (Szymanik, 2010) we predicted complexity differences among these sentences. Reciprocals with all-antecedents are expected to preferably receive a strong interpretation (Dalrymple et al., 1998), but reciprocals with proportional or numerical quantifier antecedents should be interpreted weakly. Experiment 1, where participants completed pictures according to their preferred interpretation, provides (...) evidence for these predictions. Experiment 2 was a picture verification task. The results show that the strong interpretation was in fact possible for tractable all but one-reciprocals, but not for exactly n. The last experiment manipulated monotonicity of the quantifier antecedents. (shrink)

In three experiments, we investigated the computational complexity of German reciprocal sentences with different quantificational antecedents. Building upon the tractable cognition thesis (van Rooij, 2008) and its application to the verification of quantifiers (Szymanik, 2010) we predicted complexity differences among these sentences. Reciprocals with all-antecedents are expected to preferably receive a strong interpretation (Dalrymple et al., 1998), but reciprocals with proportional or numerical quantifier antecedents should be interpreted weakly. Experiment 1, where participants completed pictures according to their preferred interpretation, provides (...) evidence for these predictions. Experiment 2 was a picture verification task. The results show that the strong interpretation was in fact possible for tractable all but one-reciprocals, but not for exactly n. The last experiment manipulated monotonicity of the quantifier antecedents. (shrink)

This article utilizes the case of Ms H. to examine the contrasting ways that surrogate decision makers move from simply hearing information about the patient to actually knowing and understanding the patient’s medical condition. The focus of the case is on a family’s request to actually see the patient’s wounds instead of being told about the wounds, and the role of clinical ethicists in facilitating this request. We argue that clinical ethicists have an important role to play in the work (...) of converting information into knowledge and that this can serve as a valuable way forward in the midst of seemingly intractable conflicts in the medical setting. (shrink)