Online research in philosophy

The discovery of Earth-sized extrasolar planets orbiting distant stars will merit an expansion of the sphere of entities worthy of moral consideration. Although it will be a long time, if ever, before humans visit these planets, it is nevertheless worthwhile to develop an environmental ethic that encompasses these planets, as this ethic reflects on our view of life on Earth and elsewhere. A particularly significant case would be a planet that displays spectroscopic signatures of life, although the discovery of many lifeless planets might itself intensify the value of life on Earth. A derivation of Schweitzer’s general principle of “reverence for life” and similar frameworks are appropriate ethics with which to view extrasolar planets. The development of an ethical framework for extrasolar planets might provide a means to fashion a deeper and more effective environmental ethic for Earth’s biosphere.

In the nineteenth century, astronomers thought that a planet between Mercury and the Sun was causing perturbations in the orbit of Mercury, and they introduced ‘Vulcan’ as a name for such a planet. But they were wrong: there was, and is, no intra-Mercurial planet. Still, these astronomers went around saying things like (2) Vulcan is a planet between Mercury and the Sun. Some philosophers think that, when nineteenth-century astronomers were theorizing about an intra-Mercurial planet, they created a hypothetical planet.

We compare astronomers' removal of Pluto from the listing of planets and psychiatrists' removal of homosexuality from the listing of mental disorders. Although the political maneuverings that emerged in both controversies are less than scientifically ideal, we argue that competition for "scientific authority" among competing groups is a normal part of scientific progress. In both cases, a complicated relationship between abstract constructs and evidence made the classification problem thorny.

Summary This article compares the discoveries of the planets Neptune and Pluto and the unsuccessful search of intra-Mercurial planets. Its conclusion is, that the search of intra-Mercurial planets was started on the basis of reasonable assumptions and competently pursued, that the success in the search of Neptune and Pluto and the failure in the search of intra-Mercurial planets was not due to greater competence of the successful planet searchers, but to good luck of the successful researchers and bad luck of the unsuccessful researchers.

Summary This article compares the discoveries of the planets Neptune and Pluto and the unsuccessful search of intra-Mercurial planets. Its conclusion is, that the search of intra-Mercurial planets was started on the basis of reasonable assumptions and competently pursued, that the success in the search of Neptune and Pluto and the failure in the search of intra-Mercurial planets was not due to greater competence of the successful planet searchers, but to good luck of the successful researchers and bad luck of the unsuccessful researchers.

The need for an explicit and exact definition of a planet has arise out of the growing rate of discovery of Trans-Neptunian Objects (TNOs) with physical and orbital properties comparable with those of Pluto, the smallest planet of the solar system. On July 29, 2005, the IAU Circular 8577 has announced the discovery of a TNO, named 2003UB313, bigger than Pluto; its discoverers have asserted that 2003UB313 must be regarded as the tenth planet of the solar system. Lacking of a definition of a planet, the International Astronomical Union has been unable to decide whether 2003UB313 should be classified as a planet, and no official name has been given to 2003UB313. Eventually, astronomers gathered at the 26th General Assembly of International Astronomical Union agreed on a definition of a planet, and Pluto was demoted from the role of planet. This situation is very interesting for the philosopher of science who can be an eyewitness of a real process of explication of a scientific concept. In this paper I examine various proposals for defining the concept of a planet and put them into a philosophical context. The principal philosophical results is that planet, as defined by the new official definition, is not a natural kind.

reading this article? A person who is not you but who lives on a planet called Earth, with misty mountains, fertile fields and sprawling cities, in a solar system with eight other planets? The life of this person has been identical to yours in every respect. But perhaps he or she now decides to put down this article without finishing it, while you read on. The idea of such an alter ego seems strange and implausible, but it looks as if we will just have to live with it, because it is supported by astronomical observations. The simplest and most popular cosmological model today predicts that you have a twin in a galaxy about 10 to the 1028 meters from here. This distance is so large that it is beyond astronomical, but that does not make your doppelgänger any less real. The estimate is derived from elementary probability and does not even assume speculative modern physics, merely that space is infinite (or at least sufficiently large) in size and almost uniformly filled with matter, as observations indicate. In infinite space, even the most unlikely events must take place somewhere. There are infinitely many other inhabited planets, including not just one but in- finitely many that have people with the same appearance, name and memories as you, who play out every possible permutation of your life choices.

A most unusual guide to the solar system, A Little Book of Coincidence suggests that there may be fundamental relationships between space, time, and life that have not yet been fully understood. From the observations of Ptolemy and Kepler to the Harmony of the Spheres and the hidden structure of the solar system, John Martineau reveals the exquisite orbital patterns of the planets and the mathematical relationships that govern them. A table shows the relative measurements of each planet in eighteen categories, and three pages show the beautiful dance patterns of thirty six pairs of planets and moons.