ABSTRACT Throughout the early modern period, the most widely read astronomical textbooks were Johannes de Sacrobosco's De sphaera and the Theorica planetarum, ultimately in the new form introduced by Georg Peurbach. This essay argues that the images in these texts were intended to develop an “intelligent eye.” Students were trained to transform representations of specific heavenly phenomena into moving mental images of the structure of the cosmos. Only by learning the techniques of mental visualization and manipulation could the student “see” (...) in the mind's eye the structure and motions of the cosmos. While anyone could look up at the heavens, only those who had acquired the intelligent eye could comprehend the divinely created order of the universe. Further, the essay demonstrates that the visual program of the Sphaera and Theorica texts played a significant and hitherto unrecognized role in later scientific work. Copernicus, Galileo, and Kepler all utilized the same types of images in their own texts to explicate their ideas about the cosmos. (shrink)

I propose a new perspective on the study of scientific revolutions. This is a transformation from an object-only perspective to an ontological perspective that properly treats objects and processes as distinct kinds. I begin my analysis by identifying an object bias in the study of scientific revolutions, where it takes the form of representing scientific revolutions as changes in classification of physical objects. I further explore the origins of this object bias. Findings from developmental psychology indicate that children cannot distinguish (...) processes from objects until the age of 7, but they have already developed a core system of object knowledge as early as 4 months of age. The persistence of this core system is responsible for the object bias among mature adults, i.e., the tendency to apply knowledge of physical objects to temporal processes. In light of the distinction between physical objects and temporal processes, I redraw the picture of the Copernican revolution. Rather than seeing it as a taxonomic shift from a geocentric to a heliocentric cosmology, we should understand it as a transformation from a conceptual system that was built around an object concept to one that was built around a process concept. (shrink)

The function of concepts must be taken seriously to understand the scientific practices of developing and working with concepts. Despite its significance, little philosophical attention has been paid to the function of concepts. A notable exception is Brigandt (2010), who suggests incorporating the epistemic goal pursued with the concept’s use as an additional semantic property along with the reference and inferential role. The suggestion, however, has at least two limitations. First, his proposal to introduce epistemic goals as the third component (...) of concepts lacks independent grounding, except to account for the rationality of semantic change (the Grounding Problem). Second, it is hardly justified to consider epistemic goals as a semantic property (the Misplacement Problem). To remedy these predicaments, we suggest a new perspective that takes concepts as cognitive entities with a 2-layered structure rather than as merely linguistic entities and develop an account of the function of concepts. We provide empirical evidence showing that functional information affects our cognitive processes. It is claimed that the function of concepts is not a semantic property but a type of meta-information regulating a body of concept-constitutive information. (shrink)

I propose a new perspective with which to understand scientific revolutions. This is a conversion from an object-only perspective to one that properly treats object and process concepts as distinct kinds. I begin with a re-examination of the Copernican revolution. Recent findings from the history of astronomy suggest that the Copernican revolution was a move from a conceptual framework built around an object concept to one built around a process concept. Drawing from studies in the cognitive sciences, I then show (...) that process concepts are independent of object concepts, grounded in specific regions of the brain and involving unique representational mechanisms. There are cognitive obstacles to the transformation from object to process concepts, and an object bias—a tendency to treat processes as objects—makes this kind of conceptual change difficult. Consequently, transformation from object to process concepts is disruptive and revolutionary. Finally, I explore the implications of this new perspective on scientific revolutions for both the history and philosophy of science.Keywords: Scientific revolutions; Process concepts; Object concepts; Object bias; Copernican revolution. (shrink)

The year 2009 marks the 400th anniversary of the publication of one of the most revolutionary scientific texts ever written. In this book, appropriately entitled, Astronomia nova, Johannes Kepler developed an astronomical theory which departs fundamentally from the systems of Ptolemy and Copernicus. One of the great innovations of this theory is its dependence on the science of optics. The declared goal of Kepler in his earlier publication, Paralipomena to Witelo whereby The Optical Part of Astronomy is Treated, was to (...) solve difficulties and expose illusions astronomers face when conducting astronomical observations with optical instruments. To avoid observational errors that had plagued the antiquated measuring techniques for calculating the apparent diameter and angular position of the luminaries, Kepler designed a novel device: the ecliptic instrument. In this paper we seek to shed light on the role optical instruments play in Kepler's scheme: they impose constraints on theory, but at the same time render astronomical knowledge secure. To get a comprehensive grasp of Kepler's astonishing achievements it is required to widen the approach to his writings and study Kepler not only as a mathematico-physical astronomer, but also as a designer of instruments and a practicing observer. (shrink)

According to the received view, the first spyglass was assembled without any theory of how the instrument magnifies. Galileo, who was the first to use the device as a scientific instrument, improved the power of magnification up to 30 times. How did he accomplish this feat? Galileo does not tell us what he did. We hold that such improvement of magnification is too intricate a problem to be solved by trial and error, accidentally stumbling upon a complex procedure. We construct (...) a plausibility argument and submit that Galileo had a theory of the telescope. He could develop it by analogical reasoning based on the phenomenon of reflection in mirrors—as it was put to use in surveying instruments—and applied to refraction in sets of lenses. Galileo could appeal to this analogy and assume Della Porta’s theory of refraction. He could thus turn the spyglass into a revolutionary scientific instrument—the telescope. (shrink)

In separate reviews of The Copernican Question published in the Summer 2012 issue of this journal, Noel Swerdlow and John Heilbron find little that meets their approval while failing to provide readers with a full and accurate summary of the book’s major claims and arguments.* The reviewers engage in an exercise in deconstructive surgery, essentially breaking down and reconstituting the work into separate studies. Swerdlow, who devotes most of his twenty-five page treatment to chapter 3 (with brief side-glances at the (...) introduction, chapters 1, 8, and 11), leaves the impression that my book is almost entirely about Copernicus. Heilbron, who confines himself mostly to what I have to say about Galileo, identifies a .. (shrink)

The year 2009 marks the 400th anniversary of the publication of one of the most revolutionary scientific texts ever written. In this book, appropriately entitled, Astronomia nova, Johannes Kepler developed an astronomical theory which departs fundamentally from the systems of Ptolemy and Copernicus. One of the great innovations of this theory is its dependence on the science of optics. The declared goal of Kepler in his earlier publication, Paralipomena to Witelo whereby The Optical Part of Astronomy is Treated , was (...) to solve difficulties and expose illusions astronomers face when conducting astronomical observations with optical instruments. To avoid observational errors that had plagued the antiquated measuring techniques for calculating the apparent diameter and angular position of the luminaries, Kepler designed a novel device: the ecliptic instrument. In this paper we seek to shed light on the role optical instruments play in Kepler's scheme: they impose constraints on theory, but at the same time render astronomical knowledge secure. To get a comprehensive grasp of Kepler's astonishing achievements it is required to widen the approach to his writings and study Kepler not only as a mathematico-physical astronomer, but also as a designer of instruments and a practicing observer. (shrink)