Shoot an arrow at a wall, and then paint a target around it so that the arrow sticks squarely in the bull's eye. Alternatively, paint a fixed target on a wall, and then shoot an arrow so that it sticks squarely in the bull's eye. How do these situations differ? In both instances the precise place where the arrow lands is highly improbable. Yet in the one, one can do no better than attribute the arrow's landing to chance, whereas in (...) the other one rightly attributes the arrow's landing to the archer's skill. ;Highly improbable events occur all the time, and by themselves may legitimately be attributed to chance. Yet when an event also conforms to a pattern given independently of that event , one rightly refuses to attribute the event to chance. Patterns given independently of events are called specifications. This dissertation explicates the relation of independence between specification and event, and sets precise bounds on what may count as a probability small enough to eliminate chance. Although this dissertation connects with how statistics eliminates chance, it considerably extends and clarifies the range of application for chance-elimination arguments based on small probabilities. ;The dual notions of specification and small probability together help justify a regulative principle of probability called the Law of Small Probability, which asserts that specified events of small probability do not occur by chance. This principle engenders a form of inference called the design inference, and a mode of explanation called design. To infer design in explaining an event is to eliminate decisively explanations of that event which appeal to law-like regularities or chance. (shrink)

The design inference uncovers intelligent causes by isolating their key trademark: specified events of small probability. Just about anything that happens is highly improbable, but when a highly improbable event is also specified undirected natural causes lose their explanatory power. Design inferences can be found in a range of scientific pursuits from forensic science to research into the origins of life to the search for extraterrestrial intelligence. This challenging and provocative 1998 book shows how incomplete undirected causes (...) are for science and breathes new life into classical design arguments. It will be read with particular interest by philosophers of science and religion, other philosophers concerned with epistemology and logic, probability and complexity theorists, and statisticians. (shrink)

The design inference uncovers intelligent causes by isolating the key trademark of intelligent causes: specified events of small probability. Just about anything that happens is highly improbable, but when a highly improbable event is also specified (i.e., conforms to an independently given pattern) undirected natural causes lose their explanatory power. Design inferences can be found in a range of scientific pursuits from forensic science to research into the origins of life to the search for extraterrestrial intelligence.

How are inferences to design affected when one makes the (plausible) assumption that the universe is spatially infinite? I will show that arguments for the existence of God based on the improbable development of life don’t go through. I will also show that the model of design inferences promulgated by William Dembski is flawed. My model for design inferences has the (desirable) consequence that there are circumstances where a seeming miracle can count as evidence (...) for the existence of God, even if one would expect that type of event to naturalistically occur in a spatially infinite universe. (shrink)

This paper addresses two main questions. How does one determine that something has the features it does as a result of design, as opposed to for example chance? How are inferences to design affected when one makes the assumption that the universe is spatially infinite? I will show that arguments for the existence of God based on the improbable development of life don’t go through under the supposition that the universe is spatially infinite. I will also show (...) that the model of design inferences promulgated by William Dembski is flawed, because it has the consequence that one can never infer design in a spatially infinite universe. My model for design inferences has the consequence that there are circumstances where a seeming miracle can count as evidence for the existence of God, even if one would expect that type of event to naturalistically occur in a spatially infinite universe. (shrink)

This article considers the main methodological objections against the theory of intelligent design. In general, they claim that it lacks a scientific character and they emphasize that design cannot be detected using scientific tools. The critics focus on showing that intelligent design violates various methodological criteria. In response to these objections, this article examines the methodological claim made by its proponents that the characteristic effects of the designer’s activity do provide a sufficient basis for inferring design. (...) This paper also argues that the procedure of inferring that a certain feature has been designed by a supernatural being does not differ in principle from design-detection procedures in other spheres of research. (shrink)

As every philosopher knows, “the design argument” concludes that God exists from premisses that cite the adaptive complexity of organisms or the lawfulness and orderliness of the whole universe. Since 1859, it has formed the intellectual heart of creationist opposition to the Darwinian hypothesis that organisms evolved their adaptive features by the mindless process of natural selection. Although the design argument developed as a defense of theism, the logic of the argument in fact encompasses a larger set of (...) issues. William Paley saw clearly that we sometimes have an excellent reason to postulate the existence of an intelligent designer. If we find a watch on the heath, we reasonably infer that it was produced by an intelligent watchmaker. This design argument makes perfect sense. Why is it any different to claim that the eye was produced by an intelligent designer? Both critics and defenders of the design argument need to understand what the ground rules are for inferring that an intelligent designer is the unseen cause of an observed effect. (shrink)

Did God create life? Or did life arise via naturalistic processes, along the lines of random mutation and natural selection as suggested by Darwin? Intelligent design proponents attempt to use William Dembski’s design inference to argue that the existence of intelligent life is due to design. I will argue that the design inference is flawed, because it does not take into account the fact that the universe is spatially infinite.

Intelligent design theorist William Dembski hasproposed an ``explanatory filter'' fordistinguishing between events due to chance,lawful regularity or design. We show that ifDembski's filter were adopted as a scientificheuristic, some classical developments inscience would not be rational, and thatDembski's assertion that the filter reliablyidentifies rarefied design requires ignoringthe state of background knowledge. Ifbackground information changes even slightly,the filter's conclusion will vary wildly.Dembski fails to overcome Hume's objections toarguments from design.

Sections include: experiments and generalised causal inference; statistical conclusion validity and internal validity; construct validity and external validity; quasi-experimental designs that either lack a control group or lack pretest observations on the outcome; quasi-experimental designs that use both control groups and pretests; quasi-experiments: interrupted time-series designs; regresssion discontinuity designs; randomised experiments: rationale, designs, and conditions conducive to doing them; practical problems 1: ethics, participation recruitment and random assignment; practical problems 2: treatment implementation and attrition; generalised causal inference: a grounded theory; (...) generalised causal inference: methods for single studies; generalised causal inference: methods for multiple studies; a critical assessment of our assumptions. (shrink)

Probabilities are numbers between 0 and 1 that attach to events. Events always occur with respect to a reference class of possibilities. Consider a die with faces 1 through 6. The reference class of possibilities in this case can be represented by the set {1, 2, 3, 4, 5, 6}. Any subset of this reference class then represents an event. For instance, the event Eodd, i.e., “an odd number was tossed,” corresponds to {1, 3, 5}. Such an event is said (...) occur if any one of its outcomes occurs, i.e., if either a 1 is tossed or a 3 or a 5. Outcomes can therefore be represented as singleton sets, i.e., sets with only one element. Thus, the outcomes associated with Eodd = {1, 3, 5} are E1 = {1}, E3 = {3}, and E5 = {5}. Outcomes are sometimes also called elementary events. Events include not only outcomes but also composite events like Eodd that include more than one outcome. (shrink)

Novice designers produced a sequence of sketches while inventing a logo for a novel brand of soft drink. The sketches were scored for the presence of specific objects, their local features and global composition. Self‐assessment scores for each sketch and art critics' scores for the end products were collected. It was investigated whether the design evolves in an essentially random fashion or according to an overall heuristic. The results indicated a macrostructure in the evolution of the design, characterized (...) by two stages. For the majority of participants, the first stage is marked by the introduction and modification of novel objects and their local and global aspects; the second stage is characterized by changes in their global composition. The minority that showed the better designs has a different strategy, in which most global changes were made in the beginning. Although participants did not consciously apply these strategies, their self‐assessment scores reflect the stages of the process. (shrink)

Novice designers produced a sequence of sketches while inventing a logo for a novel brand of soft drink. The sketches were scored for the presence of specific objects, their local features and global composition. Self‐assessment scores for each sketch and art critics' scores for the end products were collected. It was investigated whether the design evolves in an essentially random fashion or according to an overall heuristic. The results indicated a macrostructure in the evolution of the design, characterized (...) by two stages. For the majority of participants, the first stage is marked by the introduction and modification of novel objects and their local and global aspects; the second stage is characterized by changes in their global composition. The minority that showed the better designs has a different strategy, in which most global changes were made in the beginning. Although participants did not consciously apply these strategies, their self‐assessment scores reflect the stages of the process. (shrink)

Novice designers produced a sequence of sketches while inventing a logo for a novel brand of soft drink. The sketches were scored for the presence of specific objects, their local features and global composition. Self‐assessment scores for each sketch and art critics' scores for the end products were collected. It was investigated whether the design evolves in an essentially random fashion or according to an overall heuristic. The results indicated a macrostructure in the evolution of the design, characterized (...) by two stages. For the majority of participants, the first stage is marked by the introduction and modification of novel objects and their local and global aspects; the second stage is characterized by changes in their global composition. The minority that showed the better designs has a different strategy, in which most global changes were made in the beginning. Although participants did not consciously apply these strategies, their self‐assessment scores reflect the stages of the process. (shrink)

Dene Bebbbington explains, and criticises, the intelligent design creationism of William Dembski.

In a recent article, Graham Oppy offers a lucid and intriguing examination of William Paley's design argument. Oppy sets two goals for his article. First, he sets out to challenge the "almost universal assumption" that Paley's argument is inductive by revealing it actually to be a deductive argument. Second, he attempts to expose Paley's argument as manifestly poor when interpreted in this way. I will argue that Oppy is unsuccessful in accomplishing his first goal, leaving his second goal quite (...) irrelevant. Contrary to Oppy's interpretation, Paley's argument is best interpreted as an inference to the best explanation. (shrink)

In informal terms, abductive reasoning involves inferring the best or most plausible explanation from a given set of facts or data. It is a common occurrence in everyday life and crops up in such diverse places as medical diagnosis, scientific theory formation, accident investigation, language understanding, and jury deliberation. In recent years, it has become a popular and fruitful topic in artificial intelligence research. This volume breaks new ground in the scientific, philosophical, and technological study of abduction. It presents new (...) ideas about inferential and information-processing foundations for knowledge and certainty. The authors argue that knowledge arises from experience by processes of abductive inference, in contrast to the view that it arises non-inferentially, or that deduction and inductive generalization are enough to account for knowledge. Much AI research is hypothetical, so the importance of this book is that it reports key discoveries about abduction that have been made as a result of designing, building, testing, and analyzing actual working knowledge-based systems for medical diagnosis and other abductive tasks. The book tells the story of six generations of increasingly sophisticated generic abduction machines, RED-1, RED-2, PEIRCE, MDX2, TIPS, QUAWDS, and the discovery of reasoning strategies that make it computationally feasible to form well-justified composite explanatory hypotheses, despite the threat of combinatorial explosion. The final chapter argues that perception is logically abductive and presents a layered-abduction computational model of perceptual information processing. This book will be of great interest to researchers in AI, cognitive science, and philosophy of science. (shrink)

Kant’s attempts to formulate a conception of the harmony of nature and freedom have two logical presuppositions. The first presupposition is separation of ought and is, which provides a logical formulation of the separation of freedom and nature. Kant might well have settled on the view that the separation between nature and freedom cannot be bridged. Why did Kant attempt to overcome said separation? The second presupposition of Kant’s project to bridge nature and freedom involves an ought→can inference, stating that (...) moral obligation implies the possibility of its fulfillment. There are at least two ways this inference can be understood. There is a weak sense of the inference, stating that no one is obliged to do the impossible. There is also a very strong sense of the inference, stating that if a moral obligation is found to obtain, it must then be possible to fulfill it. Kant interprets the ought→can inference in this strong as well as in the weak sense. Nature, the law-governed totality of what exists, must be understood as able to provide a suitable field for moral realization. The isomorphism between the lawfulness of nature and that of moral freedom animate Kant’s account of moral judgment, and will provide the main focus of the current investigation. Kant conceives of nature and freedom as twin kingdoms, thus providing a theoretical model validating this ought→can inference. The weaker sense of this ought→can inference does justice to moral judgment without requiring the awesome task of bridging nature and freedom. Why, then, should we maintain the strong ought→can inference in our post-Kantian situation? I suggest that Kant’s insistence on the strong ought→can inference may yield an ethical approach to the ever more powerful ways in which human beings technologically transform nature, including human nature itself. (shrink)

Kant’s attempts to formulate a conception of the harmony of nature and freedom have two logical presuppositions. The first presupposition is separation of ought and is, which provides a logical formulation of the separation of freedom and nature. Kant might well have settled on the view that the separation between nature and freedom cannot be bridged. Why did Kant attempt to overcome said separation? The second presupposition of Kant’s project to bridge nature and freedom involves an ought→can inference, stating that (...) moral obligation implies the possibility of its fulfillment. There are at least two ways this inference can be understood. There is a weak sense of the inference, stating that no one is obliged to do the impossible. There is also a very strong sense of the inference, stating that if a moral obligation is found to obtain, it must then be possible to fulfill it. Kant interprets the ought→can inference in this strong as well as in the weak sense. Nature, the law-governed totality of what exists, must be understood as able to provide a suitable field for moral realization. The isomorphism between the lawfulness of nature and that of moral freedom animate Kant’s account of moral judgment, and will provide the main focus of the current investigation. Kant conceives of nature and freedom as twin kingdoms, thus providing a theoretical model validating this ought→can inference. The weaker sense of this ought→can inference does justice to moral judgment without requiring the awesome task of bridging nature and freedom. Why, then, should we maintain the strong ought→can inference in our post-Kantian situation? I suggest that Kant’s insistence on the strong ought→can inference may yield an ethical approach to the ever more powerful ways in which human beings technologically transform nature, including human nature itself. (shrink)

Change, Choice and Inference develops logical theories that are necessary both for the understanding of adaptable human reasoning and for the design of intelligent systems. The book shows that reasoning processes - the drawing on inferences and changing one's beliefs - can be viewed as belonging to the realm of practical reason by embedding logical theories into the broader context of the theory of rational choice. The book unifies lively and significant strands of research in logic, philosophy, economics (...) and artificial intelligence. It elaborates on the relevant theories and provides a mathematically precise foundation for the thesis that large parts of theoretical reason can be subsumed under practical reason. (shrink)

Studies in astrophysical cosmology have served to reveal the incomprehensible fine-tuning of the fundamental constants and cosmological quantities which must obtain if a universe like ours is to be life-permitting. Traditionally, such fine-tuning of the universe for life would have been taken as evidence of divine design. William Dembski’s ’generic chance elimination argument’ provides a framework for evaluating the hypothesis of design with respect to the fine-tuning of the universe. On Dembski’s model the key to a design (...) inference is the elimination of the competing alternatives of physical necessity and chance. In debates over fine-tuning, the former is represented by a ’theory of everything’, which would eliminate or significantly reduce the improbabilities of fine-tuning. The latter takes the shape of the ’many worlds hypothesis’, according to which a ’world ensemble’ of universes exist, thus providing purchase for the ’anthropic principle’. This paper assesses the relative merit. (shrink)

Current debates surrounding the virtues and shortcomings of randomization are symptomatic of a lack of appreciation of the fact that causation can be inferred by two distinct inference methods, each requiring its own, specific experimental design. There is a non-statistical type of inference associated with controlled experiments in basic biomedical research; and a statistical variety associated with randomized controlled trials in clinical research. I argue that the main difference between the two hinges on the satisfaction of the comparability requirement, (...) which is in turn dictated by the nature of the objects of study, namely homogeneous or heterogeneous populations of biological systems. Among other things, this entails that the objection according to which randomized experiments fail to provide better evidence for causation because randomization cannot guarantee comparability is mistaken. (shrink)

Experimental design is one aspect of a scientific method. A well-designed, properly conducted experiment aims to control variables in order to isolate and manipulate causal effects and thereby maximize internal validity, support causal inferences, and guarantee reliable results. Traditionally employed in the natural sciences, experimental design has become an important part of research in the social and behavioral sciences. Experimental methods are also endorsed as the most reliable guides to policy effectiveness. Through a discussion of some of (...) the central concepts associated with experimental design, including controlled variation and randomization, this chapter will provide a summary of key ethical issues that tend to arise in experimental contexts. In addition, by exploring assumptions about the nature of causation and by analyzing features of causal relationships, systems, and inferences in social contexts, this chapter will summarize the ways in which experimental design can undermine the integrity of not only social and behavioral research but policies implemented on the basis of such research. (shrink)

This paper reviews current psychological theories of syllogistic inference and establishes that despite their various merits they all contain deficiencies as theories of performance. It presents the results of two experiments, one using syllogisms and the other using three-term series problems, designed to elucidate how the arrangement of terms within the premises affects performance. These data are used in the construction of a theory based on the hypothesis that reasoners construct mental models of the premises, formulate informative conclusions about the (...) relations in the model, and search for alternative models that are counterexamples to these conclusions. This theory, which has been implemented in several computer programs, predicts that two principal factors should affect performance: the figure of the premises, and the number of models that they call for. These predictions were confirmed by a third experiment. Dans cet article sont passées en revue les théories psychologiques du traitement des syllogismes. On établit qu'en dépit de leurs mérites variés toutes sont en défaut en tant que théories de la performance. On présente les résultats de deux expériences, une utilisant des syllogismes et l'autre des problémes avec des séries de trois termes conçues pour élucider comment l'arrangement des termes dans les premises affecte la performance. Ces données sont utilisées pour construire une théorie fondée sur l'hypothése que les gens construisent des modèles mentaux des premises, formulent des conclusions explicites sur les relations dans le modèle et cherchent des modèles qui seraient des contre-exemples pour leurs conclusions. Cette théorie, utilisée dans plusieurs programmes d'ordinateur, prédit que deux principaux facteurs affectent la performance: la figure des premises et le nombre de; modèles qu'ils mettent en jeu. Cette prédiction est confirmée dans les trois expériences. (shrink)

Following David Hitchcock and Stephen Toulmin, this paper takes warrants to be material inference rules. It offers an account of the form such rules should take that is designed (a) to implement the idea that an argument/inference is valid only if it is entitlement preserving and (b) to support a qualitative version of evidence proportionalism. It attempts to capture what gives warrants their normative force by elaborating a concept of reliability tailored to its account of the form such rules should (...) take. (shrink)

In "The Comparative Method" Ragin (1987) has outlined a procedure of Boolean causal reasoning operating on pure coincidence data that has meanwhile become widely known as QCA (Qualitative Comparative Analysis) among social scientists. QCA -- also in its recent form as presented in Ragin (2000) -- is designed to analyze causal structures featuring one effect and a possibly complex configuration of mutually independent direct causes of that effect. The paper at hand presents a procedure of causal reasoning that operates on (...) the same type of empirical data as QCA and that implements Boolean techniques related to the ones resorted to by QCA, yet, in contrast to QCA, the procedure introduced here successfully identifies causal structures involving both mutually dependent causes, i.e. causal chains, and multiple effects, i.e. epiphenomena. In this sense, the paper at hand generalizes QCA. (shrink)

In a world befuddled by the concept of ‘fake news’, where words like ‘post-truth’ are common parlance, it is essential that we consider exactly what we think we know, what we do not and how we come to acquire such knowledge. The analysis of truth should come from an unbiased perspective and be critical of the various shibboleths that we take to heart. Appearance and Inference aims to identify the nonsense in as many knowledge-related platitudes or false assumptions as possible (...) in just over a hundred pages. Intentionally short and aphoristic, Appearance and Inference will undoubtedly provoke debate, whether or not its readers have previously considered the nature of knowledge. It is also expected to excite its academically astute readers to develop some of the analyses further. It aims to encourage the reader to think through a number of difficult matters and to exercise their own judgment, instead of supplying answers in a pre-packaged form. Inspired by the aphoristic philosophical style of philosophers such as Wittgenstein and Nietzsche, this is a book on the theory of knowledge, written by a philosopher who has had the benefit of a scientific and forensic training. It is designed for both the professional philosopher and the general reader. (shrink)

The design argument was rebutted by David Hume. He argued that the world and its contents (such as organisms) were not analogous to human artifacts. Hume further suggested that there were equally plausible alternatives to design to explain the organized complexity of the cosmos, such as random processes in multiple universes, or that matter could have inherent properties to self-organize, absent any external crafting. William Paley, writing after Hume, argued that the functional complexity of living beings, however, defied (...) naturalistic explanations. In effect he dared anyone to come up with an alternative to his inference to design, and hence a designer, outside of nature. Charles Darwin explained the apparent design of functional complexity by his theory of natural selection. Asa Gray, however, in essays as well as in correspondence with Darwin argued that natural selection allowed for a type of ' evolutionary teleology' in which design at most could be considered the result of universal principles. F. E. Hicks updated Hume by specifically objecting to the use of design arguments by Paley. Hicks argued that the apparent design seen in nature reflected order at a deep level in nature. The design argument was briefly revived by Lawrence Henderson early in the twentieth century but he ultimately concluded that design and teleology were not necessarily mutually entailing and he retracted his design argument in favor of one that he termed ' natural teleology'. The current claims of ' intelligent design' have the same logical problems that have beset previous design arguments. If design is divorced from teleology and its discontents put behind us, then there is a possibility that the latter can have a place in the development of theories to explain the phenomena of emergent complexity. (shrink)

This article discusses the epistemology of design as a process, arguing specifically that sketching and drawing are essential modes of thinking and reasoning. It demonstrates that the commonly accepted notion of a spontaneous and intuitive vision in the mind’s eye—encapsulated in the cliché of the napkin sketch—obscures the exploratory inferences that are made while scribbling with a pencil on a sheet of paper. The draughtsperson, along with their work tools, modes of notation, specific techniques, and epistemic strategies as (...) well as the resulting design artefacts form milieus of reflection that facilitate complex processes of exploration. Case studies, including the genesis of the Mini by Alec Issigonis, samples of work by Alvar Aalto, and a reinterpretation of student sketches from a classical design study by Gabriela Goldschmidt, serve to illustrate how drawing inferences with pencil and paper occurs. (shrink)

This article discusses the epistemology of design as a process, arguing specifically that sketching and drawing are essential modes of thinking and reasoning. It demonstrates that the commonly accepted notion of a spontaneous and intuitive vision in the mind’s eye—encapsulated in the cliché of the napkin sketch—obscures the exploratory inferences that are made while scribbling with a pencil on a sheet of paper. The draughtsperson, along with their work tools, modes of notation, specific techniques, and epistemic strategies as (...) well as the resulting design artefacts form milieus of reflection that facilitate complex processes of exploration. Case studies, including the genesis of the Mini by Alec Issigonis, samples of work by Alvar Aalto, and a reinterpretation of student sketches from a classical design study by Gabriela Goldschmidt, serve to illustrate how drawing inferences with pencil and paper occurs. (shrink)

Abstractabstract:Thomas Reid, I argue in this paper, holds that the belief that the works of nature are the effects of an intelligent cause is an instinctive or natural belief that may also be rational. After presenting the details of Reid's design argument, I turn to his account of human perception of the inner states of other human beings. I argue that perceptual beliefs of inner states, and hence beliefs in mental qualities such as intelligence and wisdom, involve natural signs (...) that are both instinctive and rational. Natural signs of this sort include behaviors, artifacts, or facial expressions, which lead to belief in intelligence or design in a mind. These natural instinctive/rational beliefs are of the same kind as those that arise when one considers order in nature, and they receive support both from a general principle about causal inferences, and from the conclusion of a design argument. (shrink)

There are no established conventions for, and few examples of, indexing visual material on the basis of its form. Most image databases use keywords to describe the form or function, and access data by text-based retrieval of these keywords. An image-based approach would order the data by appearance, e.g. Shepherd (1971) and Dreyfuss (1972). A taxonomy must be created in order to apply this technique to a new data set. Previous applications have been aided by certain limiting factors on the (...) possible range of images indexed thus providing the key to a taxonomy, e.g. international pictorial signs in Dreyfuss. A fundamental principle which may be inferred from these studies is that the taxonomy needs to be related to the needs of the user, and not solely to abstract features of design. This is reflected in guidelines issued by the UK organisation The Society of Indexers. The studies also suggest the need for several approaches to classification within the same data set, e.g Dreyfuss, in which signs are located under more than one heading. (shrink)

If one investigates a process that has several causes but assumes that it has only one cause, one risks ruling out important causal factors. Three mechanisms account for this mistake: either the significance of the single cause under test is masked by noise contributed by the unsuspected and uncontrolled factors, or the process appears only when two or more causes interact, or the process appears when there are present any of a number of sufficient causes which are not mutally exclusive. (...) In ecology and evolutionary biology, experiments usually test single factor hypotheses, and many scientists apparently believe that hypotheses incorporating several factors are so much more difficult to test that to do so would not be practical. We discuss several areas in ecology and evolutionary biology in which the presupposition of simple causation has apparently impeded progress. We also examine a more mature field, the study of atherosclerosis, in which single factor studies did significantly delay progress towards understanding what now appears to be a multifactor process. The problem has three solutions: either factorial experiments, dynamic models that make quantitative predictions, response-surface methods, or all three. In choosing a definition for ‘cause’, we make a presupposition that profoundly influences subsequent observations and experimental designs. Alternative definitions of causation should be considered as contributing to potential cures for research problems. (shrink)

Probabilistic Relational Models (PRMs) are a framework for compactly representing uncertainties (actually probabilities). They result from the combination of Bayesian Networks (BNs), Object-Oriented languages, and relational models. They are specifically designed for their efficient construction, maintenance and exploitation for very large scale problems, where BNs are known to perform poorly. Actually, in large-scale problems, it is often the case that BNs result from the combination of patterns (small BN fragments) repeated many times. PRMs exploit this feature by defining these patterns (...) only once (the so-called PRM’s classes) and using them through multiple instances, as prescribed by the Object-Oriented paradigm. This design induces low construction and maintenance costs. In addition, by exploiting the classes’ structures, PRM’s state-of-the-art inference algorithm “Structured Variable Elimination” (SVE) significantly outperforms BN’s classical inference algorithms (e.g., Variable Elimination, VE; Local Conditioning, LC). SVE is actually an extension of VE that simply exploits classes to avoid redundant computations. In this article, we show that SVE can be enhanced using LC. Although LC is often thought as being outperformed by VE-like algorithms in BNs, we do think that it should play an important role for PRMs because its features are very well suited for best exploiting PRM classes. In this article, relying on Faÿ and Jaffray’s works, we show how LC can be used in conjunction with VE and deduce an extension of SVE that outperforms it for large-scale problems. Numerical experiments highlight the practical efficiency of our algorithm. (shrink)

Designing complex products involves working with uncertainties as the product, the requirements and the environment in which it is used co-evolve, and designers and external stakeholders make decisions that affect the evolving design. Rather than being held back by uncertainty, designers work, cooperate and communicate with each other notwithstanding these uncertainties by making assumptions to carry out their own tasks. To explain this, the paper proposes an adaptation of Kendall Walton’s make-believe theory to conceptualise designing as playing games of (...) make-believe by inferring what is required and imagining what is possible given the current set of assumptions and decisions, while knowing these are subject to change. What one is allowed and encouraged to imagine, conclude or propose is governed by socially agreed rules and constraints. The paper uses jet engine component design as an example to illustrate how different design teams make assumptions at the beginning of design activities and negotiate what can and cannot be done with the design. This often involves iteration – repeating activities under revised sets of assumptions. As assumptions are collectively revised, they become part of a new game of make-believe in the sense that there is social agreement that the decisions constitute part of the constraints that govern what can legitimately be inferred about the design or added to it. (shrink)

Many things in the natural world work so well that they seem to have been designed. But by what? Could nature itself, by processes including those of evolution, be the designer? Or must their complex structure and function be attributed to some intelligent designer or God? Is natural design compatible with intelligent design? How good is the argument from the presence of design to an intelligent designer? And if we could legitimately infer the probable existence of an (...) intelligent designer from the presence of design in the natural world, what could we then infer about that designer's nature? (shrink)