An opinionated survey of the state of the literature on interest-relative invariantism.

The research project of common sense or folk behavior for the specific purposes of advancing epistemology has quickly become one of the largest in experimental philosophy. This chapter explains some of this work as it relates to two positions in epistemology: contextualism and interest relative invariantism (IRI). Naturally, questions arise about the relevance of folk behavior to debates in epistemology. First, there is the dialectical issue concerning the extent to which epistemologists have in fact relied on ordinary behavior (...) in defending their theories. Second, in the cases where epistemologists have made such appeals, people can ask if they have been correct in doing so. And third, assuming correctness in this regard, there is a question about which experimental methods, if any, are pertinent for understanding folk behavior. It is taken takes for granted that epistemologists appeal to ordinary usage and that their doing so in fact informs epistemology. (shrink)

I defend interest-relative invariantism from a number of recent attacks. One common thread to my response is that interest-relative invariantism is a muchweaker thesis than is often acknowledged, and a number of the attacks only challenge very specific, and I think implausible, versions of it. Another is that a number of the attacks fail to acknowledge how many things we have independent reason to believe knowledge is sensitive to. Whether there is a defeater for someone's knowledge (...) can be sensitive to all manner of features of their environment, as the host of examples from the post-Gettier literature shows. Adding in interest-sensitive defeaters is a much less radical move than most critics claim it is. (shrink)

Relativism about knowledge-attributions is the thesis that knowledge attributions express propositions the truth of which is relative to a judge. On this view, a knowledge attribution may express a proposition that is true for one judge, and false for another. This chapter explains and criticizes various versions of relativism about knowledge attributions.

According to Interest-Relative Invariantism, whether an agent knows that p, or possesses other sorts of epistemic properties or relations, is in part determined by the practical costs of being wrong about p. Recent studies in experimental philosophy have tested the claims of IRI. After critically discussing prior studies, we present the results of our own experiments that provide strong support for IRI. We discuss our results in light of complementary findings by other theorists, and address the challenge posed (...) by a leading intellectualist alternative to our view. (shrink)

This chapter is devoted to a thorough-going comparison of Interest-Relativism Invariantism and contextualism. It argues that the contextualist is committed to a worse error-theory than the advocate of Interest-Relativism Invariantism. It concludes by arguing that neither contextualism nor Interest-Relative Invariantism helps with the problem of skepticism.

Interest-relative invariantism is the view that practical interests encroach upon knowledge. In other words, the more that is at stake for S, the harder it is for her true belief to be an instance of knowledge. Russell and Doris argue that IRI theorists are committed to indifference being knowledge-making feature of IRI, where knowledge comes easier for subjects the less they care. In this paper, I explain why indifference cases are problematic and which assumptions about IRI generate them. (...) I then argue IRI theorists can immunize themselves from indifference problems by grounding practical interests in either Aristotelianism or a restricted form of Humeanism, both of which link practical interests to some conception of well-being. I then argue that besides solving indifference problems, these approaches present a reasonable conception of practical interests, while also saving IRI theorists from abandoning plausible theses about knowledge. (shrink)

Draft (Version 1.1, October 2007): (PDF file) A reply to Jason Stanley’s Analysis criticism of my interest-relative view on vagueness.

I discuss the interest-relative account of vagueness and argue for a distinction between relational vague predicates and non-relational vague predicates depending on the kind of properties expressed by them. The strategy rests on three arguments arising from the existence of clear cases of a vague predicate, from contexts in which a different answer is required for questions about whether a vague predicate applies to an item, and whether such an item satisfies the interest of an agent, and (...) from cases where an object changes up to the point of becoming P, where P is a vague predicate. In the second part of the paper, I distinguish between relational properties and non-relational properties, and I argue for the view that some vague predicates can express non-relational properties, comparative relational properties and interest-relative properties. On the basis of these arguments, I conclude that vagueness cannot be reduced to interest-relativity. (shrink)

This chapter explains and develops a version of Interest-Relative Invariantism about knowledge, according to which whether or not someone knows that p at a certain time depends in part on what is at stake for them in being right about p at that time.

In his important book Knowledge and Practical Interests, Jason Stanley advances a proposal about knowledge and the semantics of knowledge ascriptions which he calls interest-relative invariantism. A theory of knowledge ascriptions of the form ‘A knows that S’ is invariantist.

In this paper, I present and extend Neta’s : 180–187 2007) counter-example against interest-relative invariantism. I first outline IRI, briefly explaining the content of the view and illustrating how it diverges from more classical approaches to epistemology. I then distinguish between two forms the view can take: a strong and a moderate formulation. After this, I argue that Neta’s counter-example only succeeds at undermining the strongest variant, leaving the weaker counterpart unscathed. After all of this is accomplished, I (...) extend Neta-style counter-examples to undermine a more moderate variant. I close the paper by considering and responding to several objections. (shrink)

According to what I will call a contextualist solution to the sorites paradox, vague terms are context-sensitive, and one can give a convincing dissolution of the sorites paradox in terms of this context-dependency. The reason, according to the contextualist, that precise boundaries for expressions like “heap” or “tall for a basketball player” are so difficult to detect is that when two entities are sufficiently similar (or saliently similar), we tend to shift the interpretation of the vague expression so that if (...) one counts as falling in the extension of the property expressed by that expression, so does the other. As a consequence, when we look for the boundary of the extension of a vague expression in its penumbra, our very looking has the effect of changing the interpretation of the vague expression so that the boundary is not where we are looking. This accounts for the persuasive force of sorites arguments. (shrink)

The principle of Counter-Closure embodies the widespread view that when a proposition is believed solely as the conclusion of single-premise deduction, it can be known only if the premise is also known. I raise a problem for the compatibility of Jason Stanley's Interest-Relative Invariantism (IRI) with Counter-Closure. I explore the landscape of options that might help Stanley resolve this tension and argue that a trilemma confronts Stanley: he must either (i) renounce a key intuition that lies at the (...) foundation of his view; or (ii) admit into his epistemology an IRI-specific novel brand of Gettier case; or (iii) abandon Counter-Closure. (shrink)

Classical Invariantism (CI): The truth-value of a given knowledge-ascribing (-denying) sentence is (a) invariant across conversational contexts and (b) independent of how important it is to the subject (S) that the relevant proposition (P) be true.

I propose that the meanings of vague expressions render the truth conditions of utterances of sentences containing them sensitive to our interests. For example, 'expensive' is analyzed as meaning 'costs a lot', which in turn is analyzed as meaning 'costs significantly greater than the norm'. Whether a difference is a significant difference depends on what our interests are. Appeal to the proposal is shown to provide an attractive resolution of the sorites paradox that is compatible with classical logic and semantics.

Some have seen in the divine attribute of omnirationality, identified by Alexander R. Pruss, the promise of a dissolution of the usual puzzles of petitionary prayer. Scott Davison has challenged this line of thought with a series of example cases. I will argue that Davison is only partially correct, and that the reasons for this reveal an important new way to approach the puzzles of petitionary prayer. Because explanations are typically interest-relative, there is not one correct account of (...) “answered prayer” but many, corresponding to a variety of reasons to care whether God might answer our prayers. It follows from this that the omnirationality solution can be vindicated and that puzzles of petitionary prayer that are not dissolved thereby will typically contain within themselves the seeds of their own solutions. (shrink)

This paper uses two case studies to explore an interest-relative view of taxonomy and how it complements kind pluralism in biology. First, I consider the ABC island bear, which can be correctly classified into more than one species. I argue that this classificatory pluralism can be explained by reference to the range of alternative explanatory interests in biology. In the second half of the paper, I pursue an interest-relative view of classification more generally. I then apply (...) the resultant view to a second case study: whether whales are fish. I argue that this question is not one about scientific vs folk usage, as has been assumed. I also develop a new view: that Fish should be rejected as a category, both from the point of view of biological science, and from the point of view of folk taxonomy. Along the way, I use the interest-relative view to shed light on the circumstances under which higher taxa should be accepted as legitimate categories for biological science. (shrink)

The concept of a time-relative interest is introduced by Jeff McMahan to solve certain puzzles about the badness of death. Some people (e.g. McMahan and David DeGrazia) believe that this concept can also be used to show that abortion is permissible. In this paper, I first argue that if the Time-Relative Interest Account permits abortion, then it would also permit infanticide.

The substance view is an account of personhood that regards all human beings as possessing instrinsic value and moral status equivalent to that of an adult human being. Consequently, substance view proponents typically regard abortion as impermissible in most circumstances. The substance view, however, has difficulty accounting for certain intuitions regarding the badness of death for embryos and fetuses, and the wrongness of killing them. Jeff McMahan’s time-relative interest account is designed to cater for such intuitions, and so (...) I present a proposal for strengthening the substance view by incorporating McMahan’s account – the Dual-Aspect Account of the morality of killing. I show that it resolves some important issues for the substance view while preserving its central premise of moral equality for all human beings. I then compare the Dual-Aspect Account with McMahan’s Two-Tiered Account of the morality of killing, which he derives from his time-relative interest account. (shrink)

It is well known that close relatives of terminally ill patients endure great emotional stress. Many factors, such as existential concerns, contribute to the distress of these relatives. In this study, interviews were conducted to explore experiences concerning life restrictions, emotional distress, and limited support, in a group of close relatives of patients with amyotrophic lateral sclerosis (ALS). The purpose was to identify, illuminate and clarify ethical problems related to these experiences. The results indicate that close relatives of patients with (...) ALS need someone to talk to, as well as more information about the disease and its process. Furthermore, the study illustrates how ethical problems are related to choices and conflicts, and that a process including shared decision making is often an ideal when trying to find a solution to ethical problems. (shrink)

Jeff McMahan appeals to what he calls the “Time-relative Interest Account of the Wrongness of Killing ” to explain the wrongness of killing individuals who are conscious but not autonomous. On this account, the wrongness of such killing depends on the victim’s interest in his or her future, and this interest, in turn, depends on two things: the goods that would have accrued to the victim in the future; and the strength of the prudential relations obtaining (...) between the victim at the time of the killing and at the times these goods would have accrued to him or her. More precisely, when assessing this interest, future goods should be discounted to reflect reductions in the strength of such relations. Against McMahan’s account I argue that it relies on an implausible “actualist” view of the moral importance of interests according to which satisfactions of future interests only have moral significance if they are satisfactions of actual interests. More precisely, I aim to show that the Time-relative Interest Account does not have the implications for the morality of killing that McMahan takes it to have, and implies, implausibly, that certain interest satisfactions which seem to be morally significant are morally insignificant because they are not satisfactions of actual interests. (shrink)

Pragmatic encroachment theories have a problem with evidence. On the one hand, the arguments that knowledge is interest-relative look like they will generalise to show that evidence too is interest-relative. On the other hand, our best story of how interests affect knowledge presupposes an interest-invariant notion of evidence. -/- The aim of this paper is to sketch a theory of evidence that is interest-relative, but which allows that ‘best story’ to go through with (...) minimal changes. The core idea is that the evidence someone has is just what evidence a radical interpreter says they have. And a radical interpreter is playing a kind of game with the person they are interpreting. The cases that pose problems for pragmatic encroachment theorists generate fascinating games between the interpreter and the interpretee. They are games with multiple equilibria. To resolve them we need to detour into the theory of equilibrium selection. I’ll argue that the theory we need is the theory of risk-dominant equilibria. That theory will tell us how the interpreter will play the game, which in turn will tell us what evidence the person has. The evidence will be interest-relative, because what the equilibrium of the game is will be interest-relative. But it will not undermine the story we tell about how interests usually affect knowledge. (shrink)

Don Marquis has argued most abortions are immoral, for the same reason that killing you or me is immoral: abortion deprives the fetus of a valuable future. Call this account the FLOA. A rival account is Jeff McMahan’s, time-relative interest account of the wrongness of killing. According to this account, an act of killing is wrong to the extent that it deprives the victim of future value and the relation of psychological unity would have held between the victim (...) at the time of death and herself at a later time if she had lived. The TRIA supposedly has two chief advantages over Marquis’s FLOA. First, unlike the FLOA, the TRIA does not rely on the controversial thesis that identity is what matters in survival. Second, the TRIA yields more plausible verdicts about cases. Proponents of the TRIA use the account to argue that abortion is generally permissible, because there would be little to no psychological unity between the fetus and later selves if it lived. I argue that advocates of the TRIA have failed to establish its superiority to the FLOA, for two reasons. First, the two views are on a par with respect to the thesis that identity is what matters in survival. Second, Marquis’s FLOA does not yield the counterintuitive implications about cases that advocates of the TRIA have attributed to it, and the TRIA yields its own share of implausible judgments about cases. (shrink)

Excerpt from Relativity The four chapters which follow are four lectures delivered before the Edinburgh Mathematical Colloquium on the subject of Relativity. As many of the audience had their chief interests in other branches of mathematical science, it was necessary to start ab initio. The best method appeared to be to treat the subject in the historical order; I have brought it down to the stage in which it was left by Minkowski. If I have stimulated any of my audience (...) to pursue the matter further, I shall be amply repaid for any trouble that I have taken. I wish to express my thanks to the Edinburgh Mathematical Society for the honour that they have conferred on me in inviting me to give these lectures. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works. (shrink)

Alfred North Whitehead (1861-1947) was a prominent English mathematician and philosopher who co-authored the highly influential Principia Mathematica with Bertrand Russell. Originally published in 1922, this book forms the follow-up volume to "The Principles of Natural Knowledge" (1919) and "The Concept of Nature" (1920). In it, Whitehead puts forward an alternative theory of relativity, one which goes against the heterogeneity of Einstein's later theories in deducing that 'our experience requires and exhibits a basis in uniformity'. The text is divided into (...) three parts - 'General Principles', 'Physical Applications', and 'Elementary Theory of Tensors' - and exhibits a characteristically ambitious approach in mixing various academic disciplines. This is a fascinating book that will be of value to anyone with an interest in natural science, physics, and philosophy, together with the history of science. (shrink)

Two self-paced reading experiments investigated several factors that influence the comprehension complexity of singly-embedded relative clauses (RCs) in English. Three factors were manipulated in Experiment 1, resulting in three main effects. First, object-extracted RCs were read more slowly than subject-extracted RCs, replicating previous work. Second, RCs that were embedded within the sentential complement of a noun were read more slowly than comparable RCs that were not embedded in this way. Third, and most interestingly, object-modifying RCs were read more slowly (...) than subject-modifying relative clauses. This result contradicts one of the central tenets of complexity research: that nested sentences are harder to understand than their right-branching equivalents (e.g., Miller and Chomsky 1963). It is hypothesized that this result followed from a combination of two information-flow factors: (1) background information is usually presented early in a sentence; and (2) restrictive RCs—the form of the RCs in Experiment 1—usually convey background information. Experiment 2 tested this hypothesis by comparing restrictive and non-restrictive RCs— which generally provide new information—in both subject- and objectmodifying positions. The results of the experiment were as predicted by the information-flow account: Only restrictive RCs were read more slowly when modifying objects. It is concluded that both resource and information-flow factors need to be considered in explaining RC complexity effects. (shrink)

In defending his interest-relative account of knowledge in Knowledge and Practical Interests (2005), Jason Stanley relies heavily on intuitions about several bank cases. We experimentally test the empirical claims that Stanley seems to make concerning our common-sense intuitions about these bank cases. Additionally, we test the empirical claims that Jonathan Schaffer seems to make in his critique of Stanley. We argue that our data impugn what both Stanley and Schaffer claim our intuitions about such cases are. To account (...) for these results, one must develop a better conception of the connection between a subject's interests and her body of knowledge than those offered by Stanley and Schaffer. (shrink)

Agent Relative Ethics asks what the world would look like if we adopted agent relativity wholeheartedly, clinging to no shred of absolute morality. Alastair MacIntyre's haunting image of a post-apocalyptic world, in which our knowledge of ethics has been fragmented, poses a contrast between modern morality and ancient ethics. The two stand divided along the fault line of the nature of the good. Modern ethics has placed its stake in the absolute good, while ancient ethics rests upon the foundation (...) of the relative good. Following the lead of Bernard Williams, Agent Relative Ethics identifies alienation as a disturbing symptom of the present focus upon absolute goods. It then completes the diagnosis of the malady afflicting modern moral theory by clarifying the difference between absolute and relative goods. The remainder of the book explores how agent relativity can overcome the modern fragmentation of our ethical knowledge. Not just any relative goods can rectify the modern disorder. Only shared goods, belonging to a union of individuals, are sufficiently robust to overthrow the contemporary despotism of neutral goods. These shared goods exhibit many parallels with common sense morality, including partiality, impartiality, punishment, and an antagonism toward harmfully using others together with a more lenient attitude toward foreseeing harm. The final chapters probe the conditions, often unpalatable to the modern mind, by which ethics might be restored. Agent Relative Ethics will be of interest to scholars and advanced students working in ethics and moral theory, ancient ethics, and the history of philosophy. (shrink)

Physical Relativity explores the nature of the distinction at the heart of Einstein's 1905 formulation of his special theory of relativity: that between kinematics and dynamics. Einstein himself became increasingly uncomfortable with this distinction, and with the limitations of what he called the 'principle theory' approach inspired by the logic of thermodynamics. A handful of physicists and philosophers have over the last century likewise expressed doubts about Einstein's treatment of the relativistic behaviour of rigid bodies and clocks in motion in (...) the kinematical part of his great paper, and suggested that the dynamical understanding of length contraction and time dilation intimated by the immediate precursors of Einstein is more fundamental. Harvey Brown both examines and extends these arguments, after giving a careful analysis of key features of the pre-history of relativity theory. He argues furthermore that the geometrization of the theory by Minkowski in 1908 brought illumination, but not a causal explanation of relativistic effects. Finally, Brown tries to show that the dynamical interpretation of special relativity defended in the book is consistent with the role this theory must play as a limiting case of Einstein's 1915 theory of gravity: the general theory of relativity.Appearing in the centennial year of Einstein's celebrated paper on special relativity, Physical Relativity is an unusual, critical examination of the way Einstein formulated his theory. It also examines in detail certain specific historical and conceptual issues that have long given rise to debate in both special and general relativity theory, such as the conventionality of simultaneity, the principle of general covariance, and the consistency or otherwise of the special theory with quantum mechanics. Harvey Brown' s new interpretation of relativity theory will interest anyone working on these central topics in modern physics. (shrink)

According to Zhiyi 智顗 (538–597), the founder of the Chinese Buddhist Tiantai school 天台宗, “one object is all objects;” hence, all objects are profoundly interconnected. In this paper, I critically examine Zhiyi’s metaphysics of objects as presented in the historical Tiantai texts and subsequently develop a contemporary and accessible thesis of interconnectedness by integrating Zhiyi’s views with resources from contemporary analytic philosophy, particularly relative identity. By drawing on Zhiyi’s insights and incorporating contemporary philosophical ideas, I also illustrate how historical (...) Chinese Buddhism and contemporary analytic metaphysics can be mutually informing. (shrink)

It is true that there were some important dissenting voices among physicists as well as among philosophers. Paul Langevin was one of the first who protested against calling time "the fourth dimension of space. Einstein himself admitted that the asymmetry of time is preserved even in its relativistic fusion with space when he recognized that "we cannot send wire-messages into the past." When Meyerson in the session of the French Philosophical Society of April 6, 1922 insisted on the distinction of (...) space and time even in the theory of relativity, Einstein, who attended the session, explicitly agreed. Meyerson's argument was fully developed in his book, La Déduction Relativiste, and Einstein in his highly favorable comment about it again praised Meyerson's criticism of the spatialization of time. According to Einstein, the spatialization of time is a misinterpretation of the theory of relativity, a misinterpretation committed not only by popularizers, but even by many scientists, though it is often present in their minds only implicitly. Hermann Weyl, when he was in a less Kantian mood of thought, warned against a facile confusion of space and time when he claimed that it is more accurate to speak about the 3 + 1-dimensional continuum instead of the four-dimensional entity. In the same decade, Eddington among the physicists and Whitehead, Bergson and Reichenbach among the philosophers issued similar warnings. (shrink)

Regarding the sinking lifeboat scenario involving several human beings and a dog, nearly everyone agrees that it is right to sacrifice the dog. I suggest that the best explanation for this considered judgment, an explanation that appears to time-relative interests, contains a key insight about prudential value. This insight, I argue, also provides perhaps the most promising reply to the future-like-ours argument, which is widely regarded as the strongest moral argument against abortion. Providing a solution to a longstanding puzzle (...) in value theory across species while illuminating the morality of abortion, the time-relative interest account proves worthy of sustained theoretical attention. (shrink)

In General Relativity in Hamiltonian form, change has seemed to be missing, defined only asymptotically, or otherwise obscured at best, because the Hamiltonian is a sum of first-class constraints and a boundary term and thus supposedly generates gauge transformations. By construing change as essential time dependence, one can find change locally in vacuum GR in the Hamiltonian formulation just where it should be. But what if spinors are present? This paper is motivated by the tendency in space-time philosophy tends to (...) slight fermionic/spinorial matter, the tendency in Hamiltonian GR to misplace changes of time coordinate, and the tendency in treatments of the Einstein-Dirac equation to include a gratuitous local Lorentz gauge symmetry along with the physically significant coordinate freedom. Spatial dependence is dropped in most of the paper, both restricting the physical situation and largely fixing the spatial coordinates. In the interest of including all and only the coordinate freedom, the Einstein-Dirac equation is investigated using the Schwinger time gauge and Kibble-Deser symmetric triad condition are employed as a \ version of the DeWitt-Ogievetsky-Polubarinov nonlinear group realization formalism that dispenses with a tetrad and local Lorentz gauge freedom. Change is the lack of a time-like stronger-than-Killing field for which the Lie derivative of the metric-spinor complex vanishes. An appropriate \-friendly form of the Rosenfeld-Anderson-Bergmann-Castellani gauge generator G, a tuned sum of first class-constraints, is shown to change the canonical Lagrangian by a total derivative, implying the preservation of Hamilton’s equations. Given the essential presence of second-class constraints with spinors and their lack of resemblance to a gauge theory, it is useful to have an explicit physically interesting example. This gauge generator implements changes of time coordinate for solutions of the equations of motion, showing that the gauge generator makes sense even with spinors. (shrink)

I argue for the consistency of frege's treatments of identity and number. Specifically, I argue that geach is wrong in suggesting that frege's insights about number should have led him to the doctrine of relative identity.

This chapter considers Geach's claims solely as pertaining to the philosophy of language and philosophical logic, though much of the interest of the concept of relative identity concerns its applicability to other areas: the metaphysical controversy about personal identity and the debate in philosophical theology on the doctrine of the Trinity. It describes Geach's views under six headings: the non‐existence of absolute identity; the sortal relativity of identity; the derelativization thesis; the counting thesis; the thesis of the irreducibility (...) of restricted quantification; and the 'name for an A'/'name of an A' distinction. The sortal relativity thesis depends for its significance on the distinction between sortal terms and non‐sortal terms. An important component of Geach's position is his thesis that for any sortal term 'A' there is a distinction between restricted quantification over As and unrestricted quantification over things that are As. (shrink)

In this paper, I develop an interest-relative theory of justification in order to answer the question, “How can I maintain that P when someone whom I consider to be my epistemic peer maintains that not-P?” The answer to this question cannot be determined by looking at evidence alone, I argue, since justification cannot be determined by looking at evidence alone. Rather, in order to determine whether a subject S is justified in believing that P at time t, we (...) need to assess her evidence in favour of P in proportion to her interest in P. Dans cet article, je développe sur la question de la justification une théorie reliée à l’intérêt afin de répondre à la question suivante : «comment puis-je affirmer que P quand quelqu’un que je considère comme mon homologue épistémique soutient que non-P?» Je soutiens que la réponse à cette question ne peut pas être déterminée à partir des seuls éléments de preuve, puisque la justification ne peut être déterminée en examinant les données seules. Au contraire, afin de déterminer si un sujet S est justifié à croire que P au temps t, nous devons évaluer son témoignage en faveur de P en proportion de son intérêt pour P. (shrink)

In the previous chapter, it was considered in very broad terms what can happen when the ties are cut between observability and certainty. More needs to be proved, however, before the framework developed can be applied to the types of real theories of interest: quantum mechanics, relativity, and other such highbrow creations. Particularly, close observation at the nature of those statements is needed in the corpus of practical certainties that comprise the analytical observational content of the corpus that we (...) get from the sorts of theories accepted. Consideration of choices among distinct theories is needed, if such there be, having the same analytical observational content. (shrink)

Visual experience is shaped by a number of factors that are independent of the external objects that we perceive—factors like lighting, angle of view, and the sensitivities of photoreceptors in the retina. This paper seeks to catalog, analyze, and explain the fluctuations in visual phenomenology that are due to such factors.