In this thesis I shall summarize and critically examine the central features of the theories of values of four contemporary moral philosophers: A.J. Ayer, C.L. Stevenson, R.M. Hare, and P.H. Nowell - Smith. I shall first look back, however, to the theory of moral philosophy of the most influential 'forefather' of this group, David Hume. Hume's theory stands as a challenge to moral philosophers who would assume that moral judgments are primarily, in some sense, acts of 'reason'. Although our four (...) contemporaries follow Hume in this, his challenge, in the form I shall indicate shortly, will provide the main theme for this thesis. (shrink)

The causal representative theory of perception dominated theory of knowledge for hundreds of years after it was put on the map by Descartes and Locke. It is now almost extinct. How could this happen? The theory collapsed because it could not explain how we acquire knowledge of the external world, since it presupposes a causally organized system of external objects producing sensations in us. This presupposition, however, is generally recognized as true, so that the pattern of causal inference at the (...) heart of the theory is surely justified. The theory cannot explain how we originally acquire our knowledge of the external world, but it is entitled on a second pass to correct our empirical beliefs, where necessary. This includes replacing our naive picture of the physical world with a more sophisticated scientific conception, which downgrades secondary qualities. This was, indeed, the main reason why it was originally introduced by Descartes and Locke, and has been the source of its attraction over the years. (shrink)

The contents of Scala Graduum Caloris are described, supplemented by unpublished material. Both temperature measurements by his linseed oil thermometer and those based upon his law of cooling are shown to be reasonably accurate to 300°C, but above that value they are much too low. The apparent agreement and the deviation are explained by the differences between the assumptions that Newton made in deriving his law of cooling and the conditions in which he used it. Newton's attempts to link terrestrial (...) and celestial science in applications in the Principia are shown to fail from his confounding the concepts of temperature, heat and radiant intensity and his ignorance of most factors affecting the temperature rise of irradiated materials. Other comments on varied aspects of heat, mainly published in the Queries, are set out and analysed. His originality is assessed. (shrink)