'Determination is Negation': The Adventures of a Doctrine from Spinoza to Hegel to the British Idealists

This article is a discussion of Hegel’s conception of the principle ‘omnis determinatio est negatio’, which he attributes to Spinoza. It is argued, however, that Spinoza understood this principle in a very different way from Hegel, which then sets up an interpretative puzzle: if this is so, why did he credit Spinoza with formulating it? This puzzle is resolved by paying attention to the context in which those attributions are made, while it is also shown that the British Idealists (unlike many contemporary commentators) were aware of the complexities in the Spinoza–Hegel relation on this issue. The paper also addresses some of the philosophical debates raised by this question, and the light it sheds on Hegel’s critique of Spinoza as a monist

The transition zone as a host for recycled volatiles: Evidence from nitrogen and carbon isotopes in ultra-deep diamonds from Monastery and Jagersfontein (South Africa)

Sublithospheric (ultra-deep) diamonds provide a unique window into the deepest parts of Earth's mantle, which otherwise remain inaccessible. Here, we report the first combined C- and N-isotopic data for diamonds from the Monastery and Jagersfontein kimberlites that sample the deep asthenosphere and transition zone beneath the Kaapvaal Craton, in the mid Cretaceous, to investigate the nature of mantle fluids at these depths and the constraints they provide on the deep volatile cycle. Both diamond suites exhibit very light δ13C values (down to − 26‰) and heavy δ15N (up to + 10.3‰), with nitrogen abundances generally below 70 at. ppm but varying up to very high concentrations (2520 at. ppm) in rare cases. Combined, these signatures are consistent with derivation from subducted crustal materials. Both suites exhibit variable nitrogen aggregation states from 25 to 100% B defects. Internal growth structures, revealed in cathodoluminescence (CL) images, vary from faintly layered, through distinct cores to concentric growth patterns with intermittent evidence for dissolution and regular octahedral growth layers in places. Modelling the internal co-variations in δ13C-δ15N-N revealed that diamonds grew from diverse C-H-O-N fluids involving both oxidised and reduced carbon species. The diversity of the modelled diamond-forming fluids highlights the complexity of the volatile sources and the likely heterogeneity of the deep asthenosphere and transition zone. We propose that the Monastery and Jagersfontein diamonds form in subducted slabs, where carbon is converted into either oxidised or reduced species during fluid-aided dissolution of subducted carbon before being re-precipitated as diamond. The common occurrence of recycled C and N isotopic signatures in super-deep diamonds world-wide indicates that a significant amount of carbon and nitrogen is recycled back to the deep asthenosphere and transition zone via subducting slabs, and that the transition zone may be dominated by recycled C and N

Whither philosophy?

This article considers possible future directions of philosophy, based around the experience of the author as editor of the European Journal of Philosophy for about a decade. After some discussion of the original impetus for the journal, and of how the philosophy scene has changed since it was founded in 1993, the article focuses particularly on the themes of transcendentalism and naturalism as likely to shape the philosophical debates of the future, as they have done in the past