Inference to the best explanation

Author(s):  
Jonathan Vogel

Inference to the best explanation is the procedure of choosing the hypothesis or theory that best explains the available data. The factors that make one explanation better than another may include depth, comprehensiveness, simplicity and unifying power. According to Harman (1965), explanatory inference plays a central role in both everyday and scientific thinking. In ordinary life, a person might make the inference that a fuse has blown to explain why several kitchen appliances stopped working all at once. Scientists also seem to engage in inference to the best explanation; for example, astronomers concluded that another planet must exist in order to account for aberrations in the orbit of Uranus. However, despite the suggestiveness of cases like these, the extent to which we do and should rely on inference to the best explanation is highly controversial.

Author(s):  
Michael Hauskeller

It has been argued that we have a moral obligation to explore human germline modification in order to create the best possible children. In contrast, this chapter argues that in order to flourish as human beings we need to recognize that there are many different ways of being good and that the pursuit of happiness is most likely to succeed not in the extraordinary, the larger than life and better than human and beyond average, but in the ordinary life, which has enough scope and depth to provide us with all the happiness that a human life can possibly have.


2019 ◽  
Vol 3 (2) ◽  
pp. 233-324
Author(s):  
Jonathan Hay

“Bird-tracks” and “tadpoles” are both names for ancient script. As customs changed, the script came to be used less and less, until any basis for knowledgeable discussion was lost and it was known only from hearsay. The Grand Preceptor said: “When the [forms of the] rites are lost, search for them in the countryside.” Might not ancient script be even better than the countryside?The names of dozens of artists from the tenth century have come down to us, for the most part with very little information about their lives and scarcely more about their art. Fortunately, the life and professional career of Guo Zhongshu 郭忠恕 (928–977) can be reconstructed in enough detail to give a sense of the personality of the artist and the world that he experienced. Indeed, we are doubly fortunate because Guo, it turns out, had no ordinary life. Known to art historians today primarily as one of the great painters of architectural subjects in Chinese history, Guo entered adult life in a different guise, as a brilliant young paleographer and calligrapher. This aspect of his career, no less important than his painting, is the subject of the present study. Although specialists have recognized his scholarly and calligraphic achievements, we still lack a contextualized account that incorporates what can be known of his biography and social circumstances. More important for the theme of this special issue, the material dimension of Guo's paleographic and calligraphic activities also remains to be explored. Any discussion can only be very partial, however, since no manuscripts or autograph calligraphies survive, only stone steles; fortunately, Guo's engagement with stele production is in itself of the highest historical interest. The chronologically organized text that follows tells a biographical story, with as much detail as the available sources allow, which eventually opens out onto the material world of steles, before returning to biography to recount the last chapter of Guo Zongshu's life. Rather than offering a conclusion, I end with a reflection on the materialities of transmission of paleographic and calligraphic knowledge. For the purposes of this article I have not thought it necessary to choose between the very different lenses of biography and material culture, since my goal is not to prove a thesis but to reconstruct an unfamiliar world. As I hope to show, the understanding of one person's life can enrich the understanding of artifacts associated directly and indirectly with the person, and vice versa.


1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.


Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.


Author(s):  
A. V. Crewe

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.


Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.


Author(s):  
P.R. Swann ◽  
A.E. Lloyd

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.


Author(s):  
K.C. Newton

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.


Author(s):  
D. Cherns

The use of high resolution electron microscopy (HREM) to determine the atomic structure of grain boundaries and interfaces is a topic of great current interest. Grain boundary structure has been considered for many years as central to an understanding of the mechanical and transport properties of materials. Some more recent attention has focussed on the atomic structures of metalsemiconductor interfaces which are believed to control electrical properties of contacts. The atomic structures of interfaces in semiconductor or metal multilayers is an area of growing interest for understanding the unusual electrical or mechanical properties which these new materials possess. However, although the point-to-point resolutions of currently available HREMs, ∼2-3Å, appear sufficient to solve many of these problems, few atomic models of grain boundaries and interfaces have been derived. Moreover, with a new generation of 300-400kV instruments promising resolutions in the 1.6-2.0 Å range, and resolutions better than 1.5Å expected from specialist instruments, it is an appropriate time to consider the usefulness of HREM for interface studies.


Author(s):  
H.A. Cohen ◽  
W. Chiu ◽  
J. Hosoda

GP 32 (molecular weight 35000) is a T4 bacteriophage protein that destabilizes the DNA helix. The fragment GP32*I (77% of the total weight), which destabilizes helices better than does the parent molecule, crystallizes as platelets thin enough for electron diffraction and electron imaging. In this paper we discuss the structure of this protein as revealed in images reconstructed from stained and unstained crystals.Crystals were prepared as previously described. Crystals for electron microscopy were pelleted from the buffer suspension, washed in distilled water, and resuspended in 1% glucose. Two lambda droplets were placed on grids over freshly evaporated carbon, allowed to sit for five minutes, and then were drained. Stained crystals were prepared the same way, except that prior to draining the droplet, two lambda of aqueous 1% uranyl acetate solution were applied for 20 seconds. Micrographs were produced using less than 2 e/Å2 for unstained crystals or less than 8 e/Å2 for stained crystals.


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