In disproof of the materialist principle, that common things exist unperceived, and in defence of the New Principle, Philonous here objects that it is inconceivable that a common thing should do so. Hylas replies that, on the contrary, we can and do think of, e.g., a tree standing alone as opposed to a tree being perceived by an observer. But Philonous counter-objects to this reply that it contains a contradiction, since it asserts that we can think of something which is (...) not thought of. (shrink)

Burgess, J.P. and Rosen, G. Subject with No ObjectElliott, R.Faking Nature.

According to Berkeley, then, the unconscious process of inference of the scientist goes as follows. He notices that, when he does not have his house within visual range, he cannot see it just by wishing to; and that, when he does have it within visual range and his eyes open, he cannot prevent himself from seeing it just by wishing not to. He therefore infers that he is not the efficient cause of these sensations. But, since he holds that they (...) must have some efficient cause, he concludes that this is a congeries of "material substances," which are numerically distinct and partly dissimilar from the sensations, and which exist even when unperceived, or "externally to the mind." As a psychological theory, this seems to be at any rate plausible. (shrink)

Hitherto, the standard edition of Berkeley's works has been A. C. Fraser's of 1901, published by the Oxford University Press. The chief differences between the two editions are these. Professors Luce and Jessop give of each text the latest edition published by Berkeley himself, adding all significant variations in any earlier editions in footnotes, whereas Fraser followed no uniform procedure, and sometimes combined different editions. This difference is obviously an improvement. Further, Professor Luce's edition of Berkeley's pair of notebooks, which (...) he calls Philosophical Commentaries and which Fraser called Commonplace Book of occasional metaphysical thoughts, differs radically from Fraser's; Professor Luce has also given a different, and better, text of the Theory of Vision Vindicated. Finally, Volume II of the new edition amplifies Berkeley's brief correspondence with the American philosopher, Samuel Johnson, since it contains Johnson's letters to Berkeley, in which he questions some points in Berkeley's system, whereas Fraser published Berkeley's replies only. The editors' notes and introductions are brief, and have been written with the primary aim of presenting an accurate text. This policy is welcome, since it remains all too true that, as Professor Jessop remarks, "hitherto Berkeley has been read far too little, and his expositors far too much"; which, in the case of so excellent a writer as Berkeley, is doubly a pity. (shrink)

Both these developments would have surprised Berkeley. He would have found it paradoxical that the vulgar should have rejected his vulgar immaterialism as paradoxical, since he of course believed himself to be on their side in the matter, and characterised his own philosophy as a.

Context. The identification of the sources that reionized the Universe and their specific contribution to this process are key missing pieces of our knowledge of the early Universe. Faint star-forming galaxies may be the main contributors to the ionizing photon budget during the epoch of reionization, but their escaping photons cannot be detected directly due to inter-galactic medium opacity. Hence, it is essential to characterize the properties of faint galaxies with significant Lyman continuum photon leakage up to z 4 to (...) define indirect indicators allowing analogues to be found at the highest redshift. Aims. Long gamma-ray bursts explode typically in star-forming regions of faint, star-forming galaxies. Through LGRB afterglow spectroscopy it is possible to detect directly LyC photons. Our aim is to use LGRBs as tools to study LyC leakage from faint, star-forming galaxies at high redshift. Methods. Here we present the observations of LyC emission in the afterglow spectra of GRB 191004B at z = 3:5055, together with those of the other two previously known LyC-emitting LGRB, to determine their LyC escape fraction and compare their properties. Results. From the afterglow spectrum of GRB 191004B we determine a neutral hydrogen column density at the LGRB redshift of og =17:2 0:15, and negligible extinction. The only metal absorption lines detected are C iv and Si iv. In contrast to GRB 050908 and GRB 060607A, the host galaxy of GRB 191004B displays significant Ly emission. From its Ly emission and the non-detection of Balmer emission lines we constrain its star-formation rate to 1 SFR 4:7 M yr. 1. We fit the Ly emission with a shell model and find parameters values consistent with the observed ones. The absolute LyC escape fractions we find for GRB 191004B, GRB 050908 and GRB 060607A are of 0:35+0:10.0:11, 0:08+0:05.0:04 and :20+0:05.0:05, respectively. We compare the LyC escape fraction of LGRBs to the values of other LyC emitters found from the literature, showing that LGRB afterglows can be powerful tools to study LyC escape for faint high-redshift star-forming galaxies. Indeed we could push LyC leakage studies to much higher absolute magnitudes. The host galaxies of the three LGRB presented here have all M1600 >.19:5 mag, with the GRB 060607A host at M1600 >.16 mag. LGRB hosts may therefore be particularly suitable for exploring the ionizing escape fraction in galaxies that are too faint or distant for conventional techniques. Furthermore the time investment is very small compared to galaxy studies. (shrink)

A theory of the joint measurement of quantum mechanical observables is generalized in order to make it applicable to the measurement of the local observables of field theory. Subsequently, the property of local commutativity, which is usually introduced as a postulate, is derived by means of the theory of measurement from a requirement of mutual nondisturbance, which, for local observables performed at a spacelike distance from each other, is interpreted as a requirement of macrocausality. Alternative attempts at establishing a deductive (...) relationship between relativistic causality and local commutativity are reviewed, but found wanting, either because of the assumption of an unwarranted objectivity of the object system (algebraic approach) or because of the use of a projection postulate (operational approach). Finally, the quantum mechanical nonobjectivity is related to certain features of nonlocality which are present in the formalism of quantum mechanics. (shrink)