Fichte and Schelling: The Limitations of the Wissenschaftslehre?

In 1800 Fichte and Schelling began a correspondence in which they frankly addressed their philosophical differences,1 each alleging irreparable defects in the other's system and misunderstandings of their own. Their closing exchange in 1802, after which all direct communication between the two men ceased and mutual criticism became a feature of their published writings, brought to an end what had been originally and officially, ever since 1794, a relationship of philosophical cooperation, a common radical progressive front in the Kantian aftermath, confronting a single set of critics. Concerning one thing at least, they remained in agreement: the doctrine which defines in bold their philosophical opposition is that of the reality of Nature, denied by Fichte and affirmed by Schelling. The disagreement is however by no means self-explanatory, for what it means to grant or deny Nature's reality is not, after Kant, a straightforward matter – Fichte is no Berkeleyan idealist and Schelling no Lockeian realist – and a lengthy route needs to be taken in order to understand how it evolved from what had been, to all appearances, a common post-Kantian starting point. The first two parts of my discussion trace accordingly the history of their philosophical relationship, with close attention to Schelling's earliest published works, often referred to as comprising the 'Fichtean' period in his development. The third reviews the systematic ground of their disagreement

Post-Schopenhauerian Metaphysics: Hartmann, Mainländer, Bahnsen, and Nietzsche

This chapter o|ers a synoptic view of an important strand in Schopenhauer’s legacy, the philosophical interest of which remains underappreciated: the diverse attempts of certain highly creative thinkers in the period 1860–1880 to refashion Schopenhauer’s metaphysics of will in alternative and, they argue, more satisfactory and fruitful terms. The principal works in question are von Hartmann’s Philosophy of the Unconscious (1868), Nietzsche’s The Birth of Tragedy (1872), Mainländer’s Philosophie der Erlösung (Vol. 1, 1876), and Bahnsen’s Der Widerspruch im Wissen und Wesen der Welt (1880). The author’s aim is to compare these developments systematically and relate them back to the doctrines and tensions in Schopenhauer from which they originate, in each case drawing out their original features and indicating their philosophical rationale

Supercritical Water Desalination: Model-Predicted NaCl Concentration Comparison

Freshwater availability is increasingly becoming a concern for various parts of the world. Seawater desalination is becoming more commonplace as a source for freshwater in water-stressed regions such as California and the Middle East. Reverse osmosis is the most commonly employed technology for seawater desalination thanks to its ability to operate at a large scale, producing freshwater from seawater with relative ease. There are other sources of water which need to be desalinated, however, which reverse osmosis systems cannot effectively treat. Unconventional oil and gas extraction, commonly known as fracking, produces vast amounts of wastewater with high TDS levels (approximately 100,000-300,000 mg/L) and dissolved organics, known as produced water, which cannot be effectively treated by conventional desalination technologies. Supercritical water desalination is currently being explored as a solution produced water desalination. Supercritical water desalination takes advantage of waters unique properties beyond its critical pressure and temperature which result in substantially lower solubility for inorganic salts. Designing a supercritical desalination system requires extensive knowledge of fluid properties as well as salt solubilities across a wide temperature and pressure range. Obtaining this information experimentally is expensive and time-consuming. Utilizing a high fidelity model to produce key system properties can improve desalination system design in an efficient manner. This research aims to evaluate various concentration models, and thus their underlying formulation methods, and determine which model yields the most accurate concentration results for a produced water sample across the temperature range 25-450 °C at 240 bar. It is hypothesized that an empirically-derived model will outperform a conventional thermodynamic-based model for concentration determination at these elevated conditions. This research was accomplished by comparing the predicted concentrations of a NaCl-H2O solution produced by the concentration models: HSC, PHREEQC, AspenPlus, and SoWat to experimental data across the aforementioned process conditions. The predicted NaCl concentration produced by each model was evaluated to determine its ability to accurately predict concentration at elevated conditions. The empirically-derived SoWat model predicted NaCl concentration curve outperformed the concentration curves produced HSC, PHREEQC, and AspenPlus when comparing with experimental data. This model can be confidently utilized to develop a supercritical water desalination system as its predicted results are accurate. The employment of a high fidelity model such as SoWat will drastically reduce the cost and time required to develop an effective supercritical water desalination system