Lower Pecos and Coahuila peyote: new radiocarbon dates

Peyote, a psychoactive cactus native to the Chihuahuan Desert, has been preserved from excavations at only two archaeological sites: Shumla Caves in the Lower Pecos region of southwest Texas and shelter CM-79 near Cuatro Ciénegas in Coahuila, Mexico. We determined three indistinguishable radiocarbon ages of 5160 ± 45, 5200 ± 35, and 5210 ± 35 ¹⁴C years BP, yielding a mean age of 5195 ± 20 ¹⁴C years BP for the three specimens from Shumla Caves. For one of the Cuatro Ciénegas specimens we obtained the first direct radiocarbon date of 835 ± 35 ¹⁴C years BP. This study demonstrates the use of peyote by inhabitants of the Lower Pecos region of the Chihuahuan Desert about 6000 calendar years ago, and confirms its use by inhabitants of the Cuatro Ciénegas region of the Chihuahuan Desert in Late Prehistoric times. The Shumla Caves' specimens are composed of an aggregate of ground peyote mixed with other plant material, i.e., they appear to be manufactured peyote effigies, and are definitely not intact peyote buttons.     

Hydrogen and Fuel Cell Development in China: A Review

Hydrogen and fuel cells may have a major role in the future energy market if governments give a high priority to reduction of CO₂ emissions with associated R&D investment in efficient hydrogen technologies. It is predicted that China would have the highest share of hydrogen fuel cell vehicles in 2050 if their ambitious climate and energy security policies are adopted (OECD (Organisation for Economic Co-operation and Development)/IEA (International Energy Agency) (2005) Prospects for Hydrogen and Fuel Cells (Paris: OECD Publications)). R&D in hydrogen and fuel cell technologies in China has been pushed by the central government's commitment to reduce air pollution emissions from transportation, to enhance energy security and improve national competitiveness. The paper focuses on current policies and progress on hydrogen and fuel cell development in China. Development prospects and challenges are discussed with a view to achieving better understanding of the emerging hydrogen economy.     

The rationalist tradition and the problem of induction: Karl Popper's rejection of epistemological optimism

This article evaluates Karl Popper's contribution to analytic philosophy, and outlines some of the contradictions in his work which make it difficult to locate in any particular tradition. In particular, the article investigates Popper's own claims to be a member of the rationalist tradition. Although Popper described himself as a member of this tradition, his definition of it diverged quite radically from that offered by other supporters of rationalism, like, for example, Mach, Carnap, and the logical positivists of the Vienna Circle. The reason for this was that Popper believed the rationalist tradition, if it were to remain coherent and relevant, needed to overcome the dilemma posed by Hume's problem of induction. Popper believed that this problem rendered conventional understandings of rationalism, science, and inductive reasoning incoherent. This article suggests that Popper's principal contribution to modern philosophy was to reconfigure the rationalist tradition in such a way as to circumvent the problem of induction while preserving the rationalist commitment to reason, rational debate, and objective knowledge. Popper's reconfiguration of the epistemological bases of the rationalist tradition challenged dominant understandings of rationalist and analytic philosophy, and may be appropriately understood as part of a wider move among philosophers like Quine and Putnam to challenge conventional understandings of analytic philosophy, and of what philosophy itself could and could not achieve. It also informed a vision of social and political life (and of the social and political sciences) as rooted in principles of freedom, equality, and rational debate, but which cannot be fit within the traditional ideological landscape.