We show that true colors as defined by Chevreul (1839) produce unsuspected simultaneous brightness induction effects on their immediate grey backgrounds when these are placed on a darker (black) general background surrounding two spatially separated configurations. Assimilation and apparent contrast may occur in one and the same stimulus display. We examined the possible link between these effects and the perceived depth of the color patterns which induce them as a function of their luminance contrast. Patterns of square-shaped inducers of a (...) single color (red, green, blue, yellow, or grey) were placed on background fields of a lighter and a darker grey, presented on a darker screen. Inducers were always darker on one side of the display and brighter on the other in a given trial. The intensity of the grey backgrounds varied between trials only. This permitted generating four inducer luminance contrasts, presented in random order, for each color. Background fields were either spatially separated or consisted of a single grey field on the black screen. Experiments were run under three environmental conditions: dark-adaptation, daylight, and rod-saturation after exposure to bright light. In a first task, we measured probabilities of contrast, assimilation, and no effect in a three-alternative forced-choice procedure (background appears brighter on the ‘left’, on the ‘right’ or the ‘same’). Visual adaptation and inducer contrast had no significant influence on the induction effects produced by colored inducers. Achromatic inducers produced significantly stronger contrast effects after dark-adaptation, and significantly stronger assimilation in daylight conditions. Grouping two backgrounds into a single one was found to significantly decrease probabilities of apparent contrast. Under the same conditions, we measured probabilities of the inducers to be perceived as nearer to the observer inducers. These, as predicted by Chevreul’s law of contrast, were determined by the luminance contrast of the inducers only, with significantly higher probabilities of brighter inducers to be seen as nearer, and a marked asymmetry between effects produced by inducers of opposite sign. Implications of these findings for theories which attempt to link simultaneous induction effects to the relative depth of object surfaces in the visual field are discussed. (shrink)

Poorly saturated colors are closer to a pure grey than strongly saturated ones and, therefore, appear less “colorful”. Color saturation is effectively manipulated in the visual arts for balancing conflicting sensations and moods and for inducing the perception of relative distance in the pictorial plane. While perceptual science has proven quite clearly that the luminance contrast of any hue acts as a self-sufficient cue to relative depth in visual images, the role of color saturation in such figure-ground organization has remained (...) unclear. We presented configurations of colored inducers on grey ‘test’ backgrounds to human observers. Luminance and saturation of the inducers was uniform on each trial, but varied across trials. We ran two separate experimental tasks. In the relative background brightness task, perceptual judgments indicated whether the apparent brightness of the grey test background contrasted with, assimilated to, or appeared equal (no effect) to that of a comparison background with the same luminance contrast. Contrast polarity and its interaction with color saturation affected response proportions for contrast, assimilation and no effect. In the figure-ground task, perceptual judgments indicated whether the inducers appeared to lie in front of, behind, or in the same depth with the background. Strongly saturated inducers produced significantly larger proportions of foreground effects indicating that these inducers stand out as figure against the background. Weakly saturated inducers produced significantly larger proportions of background effects, indicating that these inducers are perceived as lying behind the backgrounds. We infer that color saturation modulates figure-ground organization, both directly by determining relative inducer depth, and indirectly, and in interaction with contrast polarity, by affecting apparent background brightness. The results point towards a hitherto undocumented functional role of color saturation in the genesis of form, and in particular figure-ground percepts in the absence of chromatostereopsis. (shrink)

The paper addresses the nature of duties grounded in human rights. Rather than being protections against harm, per se, I contend that human rights largely shield against risk impositions to protected interests. “Risk imposition” is a normative idea requiring explication, but understanding dutiful action in its terms enables human rights to provide prospective policy guidance, hold institutions accountable, operate in non-ideal circumstances, embody impartiality among persons, and define the moral status of agencies in international relations. Slightly differently, I indicate a (...) general understanding of dutiful action that permits human rights to see to the tasks of an institutional morality. (shrink)

The laws which predict how the perceptual quality of figure-ground can be extracted from the most elementary visual signals were discovered by the Gestaltists, and form an essential part of their movement (see especially Metzger, 1930, and Wertheimer, 1923 translated and re-edited by Lothar Spillmann, 2009 and 2012, respectively). Distinguishing figure from ground is a prerequisite for perception of both form and space (the relative positions, trajectories, and distances of objects in the visual field. The human brain has an astonishing (...) capacity for selecting and combining a few critical visual signals to accurately represent both form and space. (shrink)

The paper considers the proper method for theorizing about criminal jurisdiction. It challenges a received understanding of how to substantiate the right to punish, and articulates an alternative account of how that theoretical task is properly conducted. The received view says that a special relationship is the ground of a tribunal’s authority to prosecute and, hence, that a normative theory of that authority is faced with identifying a distinctive relation. The alternative account locates prosecutorial standing on an institution’s capacity to (...) address the basic reasons generating criminal liability. This reframes the normative issues at stake, and has the result that various, perhaps quite heterogeneous, considerations can substantiate penal authority. It also eliminates the existence of a special relation as a necessary condition for legitimate criminal accountability. The argument proceeds by offering an analysis and account of universal jurisdiction. Not only does the alternative elegantly perform where the received view struggles, it can accommodate much of what motivates the pursuit of relational ties in existing efforts to vindicate jurisdictional conclusions. (shrink)

Judicial obligation to enforce the law is typically regarded as both unproblematic and important: unproblematic because there is little reason to doubt that judges have a general, if prima facie, obligation to enforce law, and important because the obligation gives judges significant reason to limit their concern in adjudication to applying the law. I challenge both of these assumptions and argue that norms of political legitimacy, which may be extra-legal, are irretrievably at the basis of responsible judicial reasoning.

How does morality allocate responsibility for what it requires? I am concerned here with one fundamental part of this question, namely, how morality determines responsibility when multiple agents are capable of contributing to or completing a moral task, and special relationships capable of generating duties with respect to the task are non-existent, insufficient as a moral response, or partly indeterminate. On one view, responsibility falls to the agents who can bear it with the least burden. I show why this is (...) initially attractive and mistaken. Instead, I defend an equity-based approach that accommodates the intuitions that both support and trouble the least-cost principle. One upshot is that sometimes we ought prefer a distribution of responsibility that is more expensive and less local than needed to complete the task. I illustrate the practical significance of the argument in terms of the human rights of refugees. (shrink)

Demonstrating that a developing norm is not yet well established in international law is frequently thought to show that states are not bound by the norm as law. More precisely, showing that a purported international legal norm has only limited support from well-established international legal sources is normally seen as sufficient to rebut an obligation on the part of subjects to comply with the norm in virtue of its legal status. I contend that this view is mistaken. Nascent norms of (...) international law (e.g., crystallizing norms of customary law) can be binding in much the same way as better-established doctrine. This point becomes perspicuous, I argue, once we get a clear sense of the plausible options for grounding the moral authority of international law generally. -/- This result is interesting in its own right, but it also reveals two other features of the character of state responsibility under international law. First, the distinction between legislation and compliance is less pronounced compared to domestic law. Consequently, the virtues of good governance will frequently be pertinent to determining the content of states’ obligations under international law. Second, normally more powerful and influential agents will be more strongly bound by international law than other subjects. This is an attractive result, addressing a concern that motivates many international lawyers to view international law as absolutely binding. An absolutist view international legal authority is unnecessary for showing that the most powerful and dangerous states are strongly bound by the terms of much existing law. (shrink)

Victor Vasarely's (1906–1997) important legacy to the study of human perception is brought to the forefront and discussed. A large part of his impressive work conveys the appearance of striking three-dimensional shapes and structures in a large-scale pictorial plane. Current perception science explains such effects by invoking brain mechanisms for the processing of monocular (2D) depth cues. Here in this study, we illustrate and explain local effects of 2D color and contrast cues on the perceptual organization in terms of figure-ground (...) assignments, i.e. which local surfaces are likely to be seen as “nearer” or “bigger” in the image plane. Paired configurations are embedded in a larger, structurally ambivalent pictorial context inspired by some of Vasarely's creations. The figure-ground effects these configurations produce reveal a significant correlation between perceptual solutions for “nearer” and “bigger” when other geometric depth cues are missing. In consistency with previous findings on similar, albeit simpler visual displays, a specific color may compete with luminance contrast to resolve the planar ambiguity of a complex pattern context at a critical point in the hierarchical resolution of figure-ground uncertainty. The potential role of color temperature in this process is brought forward here. Vasarely intuitively understood and successfully exploited the subtle context effects accounted for in this paper, well before empirical investigation had set out to study and explain them in terms of information processing by the visual brain. (shrink)

Ronald Dworkin once identified the basic question of jurisprudence as: ‘What, in general, is a good reason for a decision by a court of law?’ I argue that, over the course of his career, Dworkin gave an essentially sound answer to this question. In fact, he gave a correct answer to a broader question: ‘What is a good reason for a legal decision, generally?’ For judges, officials of executive and administrative agencies, lawyers, non-governmental organizations, and ordinary subjects acting in the (...) variety of legal contexts, Dworkin identified the proper basis for a legal decision, and its implications for the form of well-conducted legal reasoning. Dworkin's stance on the above questions can be characterised by two theses. I defend his view by substantiating each. The result is agnostic about the viability of other aspects of Dworkin's legal theory, as it focuses on the grounds of proper legal decision-making. Whatever the fate of his other philosophical views, Dworkin's jurisprudence includes a clear-heade... (shrink)

The “Perky effect” is the interference of visual imagery with vision. Studies of this effect show that visual imagery has more than symbolic properties, but these properties differ both spatially (including “pictorially”) and temporally from those of vision. We therefore reject both the literal picture-in-the-head view and the entirely symbolic view.

Tensions in Two Dogmas of Empiricism are not resolved in Quine's later writings. The role of simplicity remains mysterious. Naturalized epistemology is wrongly presented as the only alternative to phenomenalism, and no attempt is made to answer the objection that judgements of the rationality of human activities have no place within a naturalistic philosophy. The attempt to develop an empiricism without experience leads to an implausible behaviorism and to an unsuccessful naturalistic account of observation sentences.

How should international law figure into the practical reasoning of agents who fall under its jurisdiction? How should the existence of an international legal norm regulating some activity affect a subject’s decision-making about that activity? This is a question concerning the general moral authority of international law. It concerns not simply the kind of authority international law claims, but the character of the authority it actually has. An authority, as I will use the term, is moral obligation producing: if x (...) (e.g., a person, institution, or law) has authority over an agent, then the directives of x produce a significant reason for the agent to comply with the terms of the directive. This paper concerns the sense in which international law, and the law of nascent legal systems generally, generate moral obligations for their subjects, i.e., for those who fall under their claimed jurisdiction. (shrink)

Less salient, lower contrast disks appear to be more numerous than more salient, higher contrast disks when intermingled in equal numbers into the same display, but they are equal in perceived numerosity when segregated into different displays. Comparative judgements indicate that the apparent numerosity of the lower contrast disks is unaffected by being intermingled with high contrast disks, whereas the high contrast disks are reduced in numerosity by being intermingled with the low contrast ones. Here, we report that this illusion (...) also occurs for absolute judgements of the numerosities of displays of from 20 to 80 disks. A model based on luminance-difference contrast normalization explains the illusory loss of high-contrast items along with veridical perception of the low-contrast ones. The model correctly predicts that perceived numerosity is linearly related to the square-root of the number of disks, with the extent of the illusion depending on an attentionally-weighted function of contrast and assimilation. (shrink)

Color vision provides accurate measures of the phase and intensity of daylight, and also a means of discriminating between objects. Neither property implies that objects are colored.

The paper addresses the question of what standard of conduct is supplied by human rights morality. Since the protection of dignity-interests operates on a continuum, we require a sense, if human rights are to be practically meaningful, of where on that continuum we can say that human rights have been sufficiently seen to by prevailing institutions. I argue that human rights require relevant institutions to secure a social context where it is not rationally permissible for subjects to despair. This is (...) a matter of providing security against risks to basic interests adequate to objectively warrant an agential stance. Aside from providing a principled threshold of protection, the proffered understanding supports a distinction between human rights and justice, helps illuminate the substance of certain human rights concerned with securing the conditions for rational judgment, and enables an account of the trumping or preemptive force of human rights. (shrink)

I here address the question of how judges should decide questions before a court in morally imperfect legal systems. I characterize how moral considerations ought inform judicial reasoning given that the law may demand what it has no right to. Much of the large body of work on legal interpretation, with its focus on legal semantics and epistemology, does not adequately countenance the limited legitimacy of actual legal institutions to serve as a foundation for an ethics of adjudication. I offer (...) an adjudicative theory in the realm of non-ideal theory: I adopt a view of law that has achieved consensus in legal philosophy, make some plausible assumptions about human politics, and then consider directly the question of how judges should reason. Ultimately, I argue that judges should be cognizant of the goods that are at stake on particular occasions of adjudication and that this requires treating legal requirements transparently, i.e., as sensitive to their moral justifications. (shrink)

The 18th-century Scottish ‘common sense’ philosopher Thomas Reid argued that perception can be distinguished on several dimensions from other categories of experience, such as sensation, illusion, hallucination, mental images, and what he called ‘fancy.’ We extend his approach to eleven mental categories, and discuss how these distinctions, often ignored in the empirical literature, bear on current research. We also score each category on five properties (ones abstracted from Reid) to form a 5 × 11 matrix, and thus can generate statistical (...) measures of their mutual dependencies, a procedure that may have general interest as illustrating what we can call ‘computational philosophy.’. (shrink)

In a morally non-ideal legal system, how can law bind its subjects? How can the fact of a norm’s legality make it the case that practical reason is bound by that norm? Moreover, in such circumstances, what is the extent and character of law’s bindingness? I defend here an answer to these questions. I present a non-ideal theory of legality’s ability to produce binding reasons for action. It is not a descriptive account of law and its claims, it is a (...) normative theory of legal reasoning for particular social circumstances. The approach is, somewhat like Raz’s influential account, instrumental in character. Yet, it denies that the morally binding legal norms are, in whole or part, exclusionary reasons for the responsible subject. Law’s instrumentality must be given an alternative characterization. (shrink)

Psychophysical scales can be constructed under suitable restrictions from appropriate data, but they still do not justify privileged internal sensations.

Imposing Risk: A Normative Framework. By John Oberdiek.