4E pedagogy is being promoted in the target article by Videla, Veloz, and Pino. In my commentary, the nature of teaching and whether or not 4E cognition is radical constructivist are discussed.

Open peer commentary on the article “I Can’t Yet and Growth Mindset” by Fiona Murphy & Hugh Gash.: What Murphy and Gash are attempting to do is to solve a significant problem some students have being successful in school, one that is not often addressed in any significant way. The language used to describe the lessons has some significant departures from radical constructivism. It is, no doubt, beneficial that the students in the study may have developed improvements in self-image, but, (...) as seen in other work, the application of radical constructivism to develop and extend the work started in the study could result in more and more lasting improvements. (shrink)

Open peer commentary on the article “Constructing Constructivism” by Hugh Gash. Upshot: Gash describes some very interesting and exemplary work using RC-influenced research and practices. I worry that his third stage of a three-stage emergence of constructivist epistemology in the study of cognitive development is consistent with a distinction between focus on individual cognitive development and focus on knowledge not in the mind but in the group, inconsistent with RC. An alternative is given and the issue of an RC perspective (...) on social justice is discussed. (shrink)

In this discussion note, I examine scattered comments about evil from John Dewey’s works. After a brief consideration of what critics like Reinhold Niebuhr have said about the weaknesses of Dewey’s theodicy, I will offer my own critique. In short, I argue that Dewey subverts his own theory of inquiry when he comes to the problem of the origin and genesis of evil.

In lieu of an abstract, here is a brief excerpt of the content:542 BOOK REVIEWS sires. Rather, the Subjects need to want to do those things that bring about the Bosses' satisfaction. And this raises the question of the control of the imagination. explores the subtle power relations between controllers and the controlled, to the end of exploring ways that imagination offers control over power relationships. Yet Rorty ends with a bleak vision: we are a basically conservative species, whose capacities (...) for imagining new forms of power relationships tend to be dominated by the archetypes gleaned from our collective and individual experience, often reflecting malign structures. Even benign experiences, Rorty argues, tend to reinforce our inclination to seek refuge in submission to authority. What are we to make of this collection which stretches from philosophy of mind through Freudian analyses to a chastened Hobbesian vision of our social and moral order? There is much here to interest philosophers of mind and those who are concerned with the frontier between that field and empirical psychology. While she does not supply a theory of mind, Rorty shows clearly how much heterogeneous material such a theory must encompass. JOHN CHURCHILL Hendrix College Conway, Arkansas Faith and Reason From Plato to Plantinga: An Introduction to Reformed Epistemology. DEWEY J. HOITENGA, JR. S.U.N.Y. Press, 1991. Pp. 263. $18.95. This is an excellent and important book. Most of those who have written about the ' Reformed ' epistemology of religious belief have done so with either polemical or systematic interests in mind. That is not inappropriate, since the interests of those who have propounded Reformed epistemology have also been mainly polemical and systematic. Though here and there they have pointed to historical antecedents, they have not traced those antecedents in any detail. Hoitenga's contribution is to do exactly that. For the most part, his understanding of Reformed epistemology is accurate. He himself crisply summarizes his understanding in these words: "Its central claim is the immediacy of our knowledge of God. We do not, in the first instance, know God by inference or testimony but by direct acquaintance with him. A closely related claim fa that we cannot easily remain indifferent to the God whom we know by such direct acquaintance. Thus our knowledge of God is like our knowl- BOOK REVIEWS 543 edge of every other fundamental kind of reality-physical objects, their properties and relationships, others persons, right and wrong, good and evil, and the elementary objects of logic and mathematics. Furthermore, the claim is that everyone knows God in this way, not just the Christian believer. If someone does not believe in God, that is, does not trust in God as Christians do, this is not because one does not know God. All human beings by nature have what Calvin calls an awareness of divinity.... Although the fall has clouded over this natural awareness of God and led to the loss of faith in him, it has not eradicated this awareness. Christian faith does not alter this direct awareness of God but rather presupposes it, rejuvenates it, and enlarges it " {235). Hoitenga discusses in detail three precursors of this view: Plato, Augustine, and Calvin, thus showing that the contemporary Reformed epistemology of religious belief stands in a long intellectual tradition. Though shortly I will offer a few critical comments about his interpretations, his discussion of the three thinkers is, in each case, extremely helpful. The full view of each of these thinkers, on the matters under consideration, must be constructed from passages scattered around in a large number of different texts. Hoitenga conducts this recovery of the relevant sources and the construction of his interpretation with wide knowledge of the primary texts, with apt use of the secondary literature, and with the judiciousness and balance which such interpretation requires. Though I shall now make critical comments on three points, I view these criticisms as entirely compatible with my judgment that Hoitenga has made a very important contribution with this historical introduction to Reformed epistemology. I begin with one point in his exposition of contemporary Reformed epistemology. Plantinga observes that there are perhaps some cases in which, though a person has a prima facie right to believe some theistic proposition immediately, that right is... (shrink)

Open peer commentary on the target article “Arguments Opposing the Radicalism of Radical Constructivism” by Gernot Saalmann. Excerpt: Gernot Saalmann uses the term “radical” in the sense of something “extreme.” For example, in §1, he contrasts “radical” constructivists with “moderate” constructivists. This adjectival usage of the word “radical” as “extreme” is a slang usage from the American sub-culture called “Surfers” which originated in the late 1950s or early 1960s. “Radical,” in their slang means: “At or exceeding limits of control or (...) safety…” (Oxford English Dictionary OED 2007) . (shrink)

Open peer commentary on the target article “Who Conceives of Society?” by Ernst von Glasersfeld. Excerpt: What follows is offered as an alternative explanation of the nature and status of the concept of society. This alternative is entirely compatible with radical constructivism as described elsewhere by von Glasersfeld and some others. This is not a claim of the truth-value of this alternative interpretation, but instead is no more and no less than a claim that there is an alternative explanation that (...) fits and is useful. It is not even a claim of primacy or superiority in some comparative sense. It is merely the claim that this alternative explanation of the nature and status of the concept of society exists, is viable, and is compatible with radical constructivism: a radical constructivist’s explanation of “society.”. (shrink)

Purpose: This contribution to the Festschrift honoring Ernst von Glasersfeld gives some insight into the perpetual problem of understanding radical constructivism (RC). Parallels with the Middle Way school of Buddhism appear to shed light on this challenge. Conclusion: The hegemony realism has over the thinking of even the most highly educated in our civilization plays a major role in their failure to understand RC. Those still subject to realism in their thinking interpret statements by those in RC in ways incompatible (...) with RC. Until realists disequilibrate over mismatches between realist expectations and experiences, no alternative way of thinking is accessible to them and misinterpretations of RC will continue. Practical implications: While we cannot change someone else's understanding, in our interactions with them we can focus on creating situations in which those who do not understand us might disequilibrate. If we are successful, they are likely to begin to escape the domination of realism in their thinking. Original value: This insight may enable eventual success in our assisting others to understand RC. (shrink)

This article explores the possibility that John Dewey’s silence on the matter of which democratic means are needed to achieve democratic ends, while confusing, makes greater sense if we appreciate the notion of political technology from an anthropological perspective. Michael Eldridge relates the exchange between John Herman Randall, Jr., and Dewey in which Dewey concedes “that I have done little or nothing in this direction [of outlining what constitutes adequate political technology, but that] does not detract from (...) my recognition that in the concrete the invention of such a technology is the heart of the problem of intelligent action in political matters.” Dewey’s concession could be interpreted as an admission that he was unqualified to identify political machinery or institutions suitable for realizing his vision of democracy as a way of life. Not being able to specify adequate means to achieve lofty democratic ends is not problematic, though, if we appreciate the roots of Dewey’s work (especially Human Nature and Conduct) in the anthropological writings of Immanuel Kant and Franz Boas. For then experience reflects a myriad of social and cultural conditions such that specifying explicit means to structure that experience risks stymieing the organic development of political practice. When pressured to operationalize political technology, he chose the appropriately open-ended and, at times, frustratingly vague means of education and growth. In short, Dewey did not want his ambitious democratic vision to outstrip the possibilities of practice, so he left the task of specifying exact political technology (or which democratic means are best suited to achieve democratic ends) unfinished. (shrink)

This book traces the historical lineages of Alvin Plantinga’s religious epistemology from Plato through Augustine and Calvin. It focuses upon this epistemology as a philosophical interpretation of what is generally taken to be a narrow theological doctrine. The author provides a textually based and closely reasoned introduction to the epistemological ideas of Plato, Augustine, Calvin, Plantinga, and several other writers and shows the continuity of a certain approach to the knowledge of God; it may be called the Platonic—Augustinian—Reformed approach.

Excerpt from The Appeal to Immediate Experience: Philosophic Method in Bradley Whitehead and Dewey The insight and guidance of Professor John Herman Randall, Jr. have made this book possible. Rather than merely acknowledge my debt to him I would like to express my gratitude here for his unfailing kindness, his penetrating criticism of my efforts, and the help he has given me in clarifying the complex problems of this subject-matter. I wish also to acknowledge the kindness of the following (...) publishers in permitting me to quote from their publications: F. H. Bradley, Appearance and Reality, by Allen and Unwin Ltd.; J. H. Randall, Jr. and J. Buchler, Philosophy: An Introduction, by Barnes Noble, Inc.; F. H. Bradley, Appearance and Reality and Essays on Truth and Reality, by Clarendon Press, Oxford; F. J. E. Woodbridge, Nature and Mind, by Columbia University Press; R. W. Church, Bradley's Dialectic, by Cornell University Press; John Dewey, The Man and His Philosophy, by Harvard University Press; J. Dewey, Logic and Influence of Darwin on Philosophy, by Henry Holt Company; R. Kagey, F. H. Bradley's Logic, by R. Kagey; J. Dewey, Nature in Experience and Whitehead's Philosophy, by Longmans, Green & Co.; A. N. Whitehead, Symbolism, Modes of Thought, Adventures of Ideas, Process and Reality, T. M. Forsyth, English Philosophy, and J. H. Muirhead, Bradley's Place in Philosophy, by the Macmillan Company; A. N. Whitehead, The Concept of Nature-and An Equiry Concerning the Principles of Natural Knowledge, by the Macmillan Company and the Cambridge University Press; H. B. Haldane, Human Experience, by John Murray Ltd.; J. Goheen, Whitehead's Theory of Value, by Northwestern University Press; J. Dewey, Experience and Nature, by Open Court Publishing Co.; G. Santayana, Realm of Essence and Scepticism and Animal Faith, by Charles Scribner's Sons; and J. Dewey, "How is Mind to be Known?" The Objectivism-Subjectivism of Modern Philosophy," M. Gross, The Philosophy of A. N. Whitehead," and M. C. Otto, The Journal of Philosophy. 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)

Purpose: Often radical constructivists are confronted with arguments why radical constructivism is wrong. The present work presents a radical constructivist alternative to such arguments: a comparison of the results of two instructional practices, the standard, realist-based instruction and a radical constructivist-based instruction, both in physics courses. Design: Evidence from many studies of student conceptions in standard instruction (Duit 2004) is taken into account. In addition, diagnostic data, pre and post instruction, were collected from over 1,000 students in multiple institutions across (...) the U. S. over a period of about 15 years via an established diagnostic of conceptual understanding of motion and force. Findings: Evidence from many studies of student conceptions in standard instruction (Duit, 2004) is that little or no change in student conceptions happens in standard instruction. About half the students in the particular study reported, all science and engineering majors, experienced standard, realist-based instruction and show an average effect size of 0.6 standard deviations and an average normalized gain of 15%. The other half of the students, none of whom were science and engineering majors, experienced radical constructivist-based instruction and show an average effect size over 2.5 standard deviations and an average normalized gain over 60%. Diagnostic pre scores were nearly the same for both groups. Practical implications: The outcome, that students, neither science nor engineering majors, made changes in understanding foundational topics in physics far greater than science and engineering students, poses (1) an ethical challenge to the continued adherence to standard, realist-based instructional practices and (2) an intellectual challenge to the usefulness and appropriateness of the elitist-realist paradigm on which such standard instruction is based. Conclusion: This radical constructivist argument uses the effect of paradigms to judge their pragmatic value, not their truth-value. Based on pragmatic value, radical constructivism results in superior outcomes when applied to physics instruction. The approach to instruction can be applied generally in education. (shrink)

Context: In spite of its advantages and its ability to make valid responses to objections, radical constructivism is not mainstream. Problem: Extolling the virtues of radical constructivism and responding logically to the objections does not work. We know this from the evidence of many attempts. Our theoretical stance, radical constructivism, also suggests this approach is not likely to have much influence on realists. We cannot transmit understanding in the signals with which we attempt to communicate. How can we in radical (...) constructivism enable those outside of RC to understand our explanation of human knowing? Method: Examine our understanding of radical constructivism itself, because it is an explanation of how, why and under what circumstances people change their understandings of their experiential worlds. Results: We must find ways to direct the attention of others to situations that they cannot explain with their existing understanding of the world. Then we must create conditions conducive to their revising and testing new understandings for fit with the evidence of their experience. Implications: Since radical constructivism is a theory of human knowing, it tells us how humans develop knowledge, hence it is an answer to the questions central to this special issue. This answer is not one to be used to win in debates with realists. Radical constructivism gives us an answer to the problem of engaging realists in understanding our position, but strategies consistent with radical constructivism are not easily carried out. Developing and executing such strategies is the work at hand. (shrink)

Problem: What alternative strategies from our experiences using a Piaget-based radical constructivist pedagogy might have more and better results than the current practice of responding in debate form, each side trying to prove the other wrong? Method: Use of Slezak’s paper to illuminate the point that the central problem with the interpretation of RC generally used in such writing is that the authors seem not to be able to operate from the central tenet of RC, which is the opposite of (...) that used in realism. Description of how this failure to use the central tenet of RC results in claims that RC is irrelevant to education and to definitions of good teaching. Results: A specific approach shown to be useful in facilitating the construction of new understanding in science is adapted in order to guide interaction between an RC and a realist, which can result in the realist understanding the RC point of view. Implications: Instead of debating with critics of RC, where each side is trying to prove the other side wrong, we need to change the interaction to one in which members of opposing sides attempt to understand the other’s position. In this situation we are in a position to use a pedagogical strategy in which the realist examines her own fundamental assumption that we can know a mind-independent world, and considers the implications of a starting assumption that is exactly the opposite. (shrink)

Recent research has shown that a phase transformation of diamond to a different form of carbon is involved when diamonds are polished in the traditional fashion. The question as to how this phase transformation is activated and maintained to produce high wear rates is of great technological interest since it may radically change the way we view the processing of diamond. This paper describes the use of Raman spectroscopy to examine debris produced on the diamond polishing wheel, both during its (...) preparation and during polishing. In addition, polished diamond surfaces were examined for the possible existence of non-diamond surface layers in an attempt to identify material removal mechanisms. Raman spectroscopy proves ideal for these analyses because its relatively high spatial resolution is well suited to the analysis of small wear features and debris particles, and because of the wealth of information it reveals about chemical structure. This level of structural information has been lacking in previous analyses of diamond polishing debris. In addition to the non-diamond carbon found in the wear debris, significant quantities of two iron oxides, magnetite (Fe3O4) and haematite (α-Fe2O3), were also found. An interesting observation was that a transformation from magnetite to haematite could be induced either by using high power laser excitation or by frictional heating during polishing. It is suggested that some of the Raman peaks previously attributed to lonsdaleite might better be explained by the presence of these oxides. (shrink)

"A modern classic. Dewey's lectures have lost none of their vigor...The historical approach, which underlay the central argument, is beautifully exemplified in his treatments of the origin of philosophy."-- Philosophy and Phenomenological Research "It was with this book that Dewey fully launched his campaign for experimental philosophy."-- The New Republic Written by an eminent philosopher shortly after the shattering effects of World War I, this volume offers an insightful introduction to the concept of pragmatic humanism. Dewey presents (...) persuasive arguments against traditional philosophical constructs, suggesting their basis in self-justification. He proposes, instead, an examination of core values in terms of their ultimate effects on the self and others. This experimental philosophy was received with both outrage and acclaim for daring to mingle ethics and science. Delivered in 1919 as a series of lectures, Dewey's landmark work appears here in an enlarged edition that features an informative introduction by the author, written more than 25 years after the book's initial publication. (shrink)

The esteemed psychologist and thinker John Dewey headed for previously unexplored philosophical territory with this influential work. Written shortly after World War I, it embodies Dewey's system of pragmatic humanism and maintains that individuals can attain "a more ordered and intelligent happiness" by reconsidering the ultimate effects of their deepest beliefs and feelings. With its promise of achieving an understanding of the past and attaining a brighter future, Reconstruction in Philosophy remains ever relevant. "A modern classic." — Philosophy (...) and Phenomenological Research. (shrink)

The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into (...) two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Literature 25.2 (2001) 353-356 [Access article in PDF] Book Review The Metaphysical Club The Metaphysical Club, by Louis Menand; xii & 546 pp. New York: Farrar, Straus and Giroux, 2001, $27.00. "They didn't just want to keep the conversation going; they wanted to get to a better place" (p. 440). So much for the most prominent contemporary pragmatist, Richard Rorty, who remains unmentioned except in the acknowledgments. (...) That better place is participatory democracy (a phrase that does not appear in the book), which "means that everyone is equally in the game, but it also means that no one can opt out" (p. 441). The true name of the game is skeptical tolerance. There are no unquestionable duties or inalienable rights, no immutable natural laws, no absolute moral rules, no highest principles, no inherent virtues, no absolute standards, no stasis, no absolutely certain truth. There are no individual destinies, because the social comes before the individual, and the individual is embedded within and cannot exist without society. Scientific knowledge is always probabilistic, not necessarily because nature is indeterministic, but because we can never know enough to calculate its regularities if they exist. To wit, there are no Platonic Ideas or unchanging universals. All is change, nothing that happens is ever repeated, our general ideas and laws of nature are merely tools for getting along in the world. Above all, ideas do not refer to things, only to other ideas. What expedites our thinking is true. What expedites our acting is right. Whenever we act according to principle, rule, or law, we are making a bet that events will turn out the way [End Page 353] we think they will. If we keep this always in mind, we will never succumb to violence or war in the name of belief or principle. Whatever we believe, it could be otherwise. Such is a general summary of pragmatism as it has filtered down to the textbooks. It is (again befittingly) more or less accurate. The can-do American seeks out cash value in practical life.Oliver Wendell Holmes, Jr., William James, Charles Saunders Pierce, and John Dewey crafted the only indigenous philosophy that has so far been produced in America. Its roots are in Laplacean probability theory, Darwinian evolutionism, and Chauncey Wright's indeterminism. While James hoped to save a place for religion (if it works, go with it) and Pierce a place for God (he thought there had to be a designing intelligence to account for order), the pragmatic result is profoundly skeptical and secular. Neither Holmes nor Dewey thought that individuals imbedded in societies had any need of absolutes. Holmes said that people first decide on the basis of experience, then they deduce. Dewey said that people first behave commonsensically, then they rationalize.There is nothing as condensed as the above in Louis Menand's beautiful book on the ideas, personalities, and influence of Holmes, James, Pierce, and Dewey. I know of no clearer exposition of their ideas, and few biographers have made them come so alive. In particular, Menand's coverage of peripheral (but by no means insignificant) figures is very rich. He describes the development of graduate universities in America in detail from their autocratic beginnings to the institution of academic freedom as we know it today. University presidents, trustees, and administrators are presented luxuriously as the villains, and the professors gloriously as the heroes. Menand remarks with slight amazement that society bought the concept that professors were beholden to the public at large and not to the state or private university owners. He could have commented further on the fact that the concept of academic freedom has become virtually irrelevant in today's corporate research universities."It is a remarkable fact about the United States," Menand begins his book, "that it fought a civil war without undergoing a change in its form of government" (p. ix). This is a breathtaking fact, and I don't suppose Menand had any intent to explain it. "The Civil War swept away the slave civilization of the South, but it swept away almost the whole intellectual... (shrink)

One legacy of post-Enlightenment dualism in the universe of academic discourse is the presence of two approached to notions of duality championed by two differing camps. One camp might arbitrarily be called debunkers; the other might be labeled rationalists. The strategies of the camps are conditioned by traditional notions of inside and outside. Debunkers consider themselves outsiders, beyond a deceptive show filled with tricky mirrors. Rationalists, by contrast, spend a great deal of time among mirrors, listening to explanations from the (...) overseers, attempting to absorb sideshow language, hoping to provide acceptable analytical accounts. If debunkers are intent on discovering generative and, presumably, hidden ideological inscriptions of a given discourse—its situation on what Amiri Baraka calls the “real side” of economic exchange and world exploitative power—rationalists are concerned to study discursive products, to decode or explain them according to forms and formulas that claim to avoid general views or judgments of ideology. Differentiating the camps also is what might be called a thermal gradient: the heat of the debunker’s passion is palpable. It is unnecessary to command him, in the manner of the invisible man’s tormentor, to “Get hot, boy! Get hot!” Rationalists, by contrast, do not radiate. They appear to have nothing personal at stake and remain coolly instructive and intelligently unflappable in their analyses.This tale of an Enlightenment legacy, as I have told it, contrasts a debunking body and rationalist soul. As I have suggested in my opening sentence, however, what is at issue is not so much two actual and substantially distinctive camps as two metonyms for dual approaches to a common subject—namely, notions of duality. My claim is that the Enlightenment reflexivity of academic discourse, devoted to, say, “the Other” and conceived in dualistic terms of self-and-other, expresses itself as an opposition. Thos whom I have called debunkers gladly accept the Other’s sovereignty as a bodily and aboriginal donnée; rationalists work to discover the dynamics of “othering” engaged in by a self-indulgent Western soul. The difficulty of producing usefully analytical or political results for either camp is occasioned by their joint situation within a post-Enlightenment field. Houston A. Baker, Jr. is the Albert M. Greenfield Professor of Human Relations at the University of Pennsylvania. He is a poet whose recent volume Blues Journeys Home appeared in 1985. He is also the author of a number of studies of Afro-American literature and culture, including the forthcoming Modernism and the Harlem Renaissance. (shrink)

Consider the claim that false beliefs can be justified (JFB). According to Williamson (forthcoming), the most promising argument for JFB is something like this: (1) if p is what one disposed to know or to believe truly would believe, then believing p is justified; (2) sometimes, one disposed to know or to believe truly would believe p even though p is false; so, JFB. But there are counterexamples to (1). I argue that this isn't the most promising argument for JFB. (...) Instead, the thought is that beliefs which manifest a disposition to know or to believe truly are justified. (1) should be replaced by: (1*) if believing p manifests a disposition to know or to believe truly then believing p is justified. (1*) is immune to the counterexamples. (shrink)

PURPOSE:To report the localization of a gene causing drusen and macular degeneration in a previously undescribed North American family. METHODS:Genetic mapping studies were performed using linkage analysis in a single family with drusen and atrophic macular degeneration. RESULTS:The clinical manifestations in this family ranged from fine macular drusen in asymptomatic middle-aged individuals to atrophic macular lesions in two children and two elderly patients. We mapped the gene to chromosome 6q14 between markers D6S2258 and D6S1644. CONCLUSIONS:In a family with autosomal dominant (...) drusen and atrophic macular degeneration, the gene maps to a 3.2-cM region on chromosome 6q14. This locus appears to be distinct from, but adjacent to, the loci for cone-rod dystrophy 7 (CORD7) and North Carolina macular dystrophy (MCDR1). Future identification of the gene responsible for the disease in this family will provide a better understanding of macular degeneration. (shrink)