Age of the Earth research. Most geological samples from Earth are unable to give a direct date of the formation of Earth from the solar nebula because Earth has undergone differentiation into the core, mantle, and crust, and this has then undergone a long history of mixing and unmixing of these sample reservoirs by plate tectonics, weathering and hydrothermal circulation. All of these processes may adversely affect isotopic dating mechanisms because the sample cannot always be assumed to have remained as a closed system, by which it is meant that either the parent or daughter nuclide (a species of atom characterised by the number
The Public and its Problems what he saw as argumentation on the part of Lippman that was particularly doctrinaire and absolutist in its judgements, and saw his own philosophical pragmatism as a means by which a more accurate and realistic conception of what the public and democracy was capable of it, and its limitations. Dewey begins his argument by distinguishing between the "state," represented by elected lawmakers, and the "public," the diffuse, often incoherent body of citizens who elect the state. The public is called into being when ordinary citizens experience the negative externalities (or consequences) of exchanges beyond their control (such as market or