: Scientific observation is determined by the human sensory system, which generally relies on instruments that serve as mediators between the world and the senses. Instruments came in the shape of Heron's Dioptra, Levi Ben Gerson's Cross-staff, Egnatio Danti's Torqvetto Astronomico, Tycho's Quadrant, Galileo's Geometric Military Compass, or Kepler's Ecliptic Instrument. At the beginning of the seventeenth century, however, it was unclear how an instrument such as the telescope could be employed to acquire new information and expand knowledge about the (...) world. To exploit the telescope as a device for astronomical observations Galileo had to: 1. establish that telescopic images are not optical defects, imperfections in the eye of the observer, or illusions caused by lenses; 2. develop procedures for systematically handling errors that may occur during observation and measurement and methods of processing data. Galileo made it clear that in order to measure and interpret natural phenomena accurately, a suitable method and instrument would need to be developed. It is intriguing, therefore, to regard the Galilean telescope in this light and to discover the linkage established by Galileo among theory, method, and instrument—the telescope. Although the telescope was not invented through science, it is instructive to see how Galileo used optics to employ a theory-laden instrument for bridging the gulf between picture and scientific language, between drawing and reporting physical facts, and between merely sketching the world and actually describing it. (shrink)

It is argued that Galileo's theory of justification was a version of explanationism. Galileo's Dialogue on the Two Chief World Systems is to be read as primarily a defense of his theory of the tides. He shows how, by assuming Copernican motions, he can explain the tides, thereby justifying the endorsement of Copernicus. The crux of the argument rests on Galileo's account of explanation, which is novel in its reliance on the use of geometry. Finally, the consequences of his use (...) of geometry, and his views on the limits of knowledge, force us to conclude that if Galileo was a realist, his realism was so highly constrained as to be irrelevant. (shrink)

ArgumentA Catoptrica attributed to Euclid appears in manuscripts amongst treatises dealing with elementary astronomy. Despite this textual background, the treatise has always been read literally as a theory of mirrors, and its astronomical significance has gone unnoticed. However, optics, catoptrics, and astronomy appear strongly intermingled in sources such as, amongst others, Geminus, Theon of Smyrna, Plutarch and Cleomedes. If one compares the optical reasoning put forward in these sources to account for the formation of moonlight with arguments of Catoptrica, one (...) is able to shed new light on several principles and propositions of Catoptrica, some of which had been deemed corrupt, meaningless, and obscure. Moreover, the present analysis offers a glimpse at the context of a specific stage in the evolution of ancient catoptrics: Whether literally or by analogy, several of its results appear to have been set against a wider astronomical background, which explains the inclusion of Catoptrica in the group of texts loosely defined as “little astronomy.”. (shrink)

One of the distinctive features of modern science is a commitment to empiricism—a fundamental expectation that theoretical hypotheses will survive encounters with observations. Those that comport with the theory's explanations and predictions confirm the theory. Anomalous observations that do not fit theoretical expectations disconfirm it. Moreover, experiments can be contrived to generate observations that might serve to confirm or disconfirm a theory. Philosophers of science may disagree as to how exactly all of this is supposed to work, but the basic (...) empiricist expectation almost goes without saying. To deny it is to rule one's self out of the bounds of the scientificenterprise.Strange as it might seem to modern... (shrink)

The ArgumentThe article deals with the interrelation between Galileo and the visual arts. It presents a couple of drawings from the hand of Galileo and confronts them with Viviani's report that Galileo had not only wanted to become an artist in his youth but stayed close to the field of visual arts throughout his lifetime. In the ambiance of these drawings the famous moon watercolors are not in the dark. They represent a very acute and reasonable tool to convince the (...) people who trusted images more than words. The article ends with Panofsky's argument that it was Galileo's anti-Mannerist notion of art that evoked a repulsion of Kepler's ellipses. It tries to show that it was again an aesthetical prejudice that hindered Einstein from accepting Panofsky's theory. (shrink)

the article deals with the interrelation between galileo and the visual arts. it presents a couple of drawings from the hand of galileo and confronts them with viviani's report that galileo had not only wanted to become an artist in his youth but stayed close to the field of visual arts throughout his lifetime. in the ambiance of these drawings the famous moon watercolors are not in the dark. they represent a very acute and reasonable tool to convince the people (...) who trusted images more than words. the article ends with panofsky's argument that it was galileo's anti-mannerist notion of art that evoked a repulsion of kepler's ellipses. it tries to show that it was again an aesthetical prejudice that hindered einstein from accepting panofsky's theory. (shrink)

The ArgumentIn 1612, Lodovico Cigoli completed a fresco in the Pauline chapel of the Basilica of Santa Maria Maggiore in Rome depicting Apocalypse 12: “A woman clothed with the sun, and the moon under her feet.” He showed the crescent Moon with spots, as his friend Galileo had observed with the newly invented telescope. Considerations of the orthodox view of the perfect Moon as held by philosophers have led historians to ask why this clearly imperfect Moon in a religious painting (...) raised no eyebrows. We argue that when considered in the context of biblical interpretation and the rhetoric of the Counter-Reformation, the imperfect Moon under the woman's feet was entirely consistent with traditional interpretations of Apocalypse 12. (shrink)

: This paper continues my application of theories of concepts developed in cognitive psychology to clarify issues in Kuhn's mature account of scientific change. I argue that incommensurability is typically neither global nor total, and that the corresponding form of scientific change occurs incrementally. Incommensurability can now be seen as a local phenomenon restricted to particular points in a conceptual framework represented by a set of nodes. The unaffected parts in the framework constitute the basis for continued communication between the (...) communities supporting alternative structures. The importance of a node is a measure of the severity of incommensurability introduced by replacing it. Such replacements occur incrementally so that changes like that from the conceptual structure of Aristotelian celestial physics to the conceptual structure of Newtonian celestial physics occur in small stages over time, and for each change it is in principle possible to identify the arguments and evidence that led historical actors to make the revisions. Thus the process of scientific change is a rational one, even when its beginning and end points are incommensurable conceptual structures. It is also apparent, from a detailed examination of the conceptual structure of astronomy at the time of Copernicus, thatthe kind of conceptual difficulty identified as incommensurability may occur within a single scientific tradition as well as between two rival traditions. (shrink)