Compression of tetrahedrally bonded SiO2 liquid and silicate liquid‐crystal density inversion

We have investigated the response to pressure of liquid SiO2 by performing a quantitatively realistic Monte Carlo simulation. The model liquid was restricted to at most four‐fold Si‐O coordination by the effective imposition of an infinite potential barrier to a fifth bond. We thus obtained an unambiguous comparison of the compression mechanisms of solid and liquid tetrahedral networks. In spite of this restriction, the density of the simulated liquid exceeds that of the corresponding models of quartz, coesite and cristobalite at high pressure. The efficient compression of the liquid results from a continuous restructuring of the network that leaves the mean Si‐Si distance virtually unchanged and does not require an increase in the coordination number. The restructuring is effected by local breaking and reconnecting of bonds, a mechanism that is not available to a perfect crystal

Sartre, Marx and legal theory

Bourgeois law, according to Marx, is ideological, but this familiar claim should not be taken to assert that law is merely an epiphenomenon of a specific material formation; there exists a dialectical relationship between our free praxis and the material conditions in which we act, within which dialectic legal systems and ideologies arise. While Marxist legal theorists have investigated the material causes of capitalist legal orders, they have not developed a fine-grained model that accounts for the (re)production of legal ideologies at the level of individual, free praxis. In this dissertation, I attempt to develop such a model, utilizing tools drawn from Jean-Paul Sartre\u27s political theory. I first distinguish non-Marxist, analytical methodologies in legal theory from a Marxist dialectical methodology, arguing that certain non-Marxist theories of the nature of law, such as Thomistic natural law theory, classical Austinian positivism, and Savigny\u27s historical theory, suffer from a common methodological failing, in that they treat a given theoretical or conceptual description of the law in abstraction from the historical context in which a theory is produced, and only in the context of which is that theory fully coherent. I then contrast these theories with Marx\u27s dialectical-historical approach, arguing that Marx\u27s theory is both descriptively and methodologically more adequate, particularly when supplemented by a phenomenology of bourgeois legal forms of human mediation. Here I draw on tools developed by Sartre in his Critique of Dialectical Reason, especially his theory of practical social ensembles. Law, in Sartre\u27s theory, is a practical ensemble with the structure of an institution, and it is within this structure that the dialectic of praxis and material conditions which gives rise to bourgeois law becomes intelligible. I conclude with a discussion of the problem of rights as a primary form of human mediation, arguing for their transcendence through a form of mediation found paradigmatically in the gift