Black ravens, white shoes and scientific evidence : the Ravens Paradox and/in scientific practice

1BLACK RAVENS, WHITE SHOES AND SCIENTIFIC EVIDENCE.THE RAVENS PARADOX AND/IN SCIENTIFIC PRACTICEErik Weber, Mathieu Beirlaen&Inge De BalCentre for Logic and Philosophy of ScienceGhent University (UGent)Blandijnberg 2, B-9000 Gent , BelgiumAbstractA well-known consequence of Hempel’s account of confirmation is the RavensParadox. In this paper we discuss this paradox from the viewpointof scientific practice. The main worry, when looking at this paradox from a scientific practiceperspective, is that it seems to lead to problematic methodological advice for scientists: it seems to licence ‘indoor ornithology’. We show that this problematic advice only follows from Hempel’s account if one adoptsa suboptimal viewof what counts as evidence for anhypothesis. We present and defend a more sophisticated viewof what counts as evidence, whichtakesrandom sampling–an important methodological principle in scientific practice–into account. On this sophisticated view, the problematic methodological advice connected tothe RavensParadox is avoided

A non-transitive relevant implication corresponding to classical logic consequence

In this paper we first develop a logic independent account of relevant implication. We propose a stipulative denition of what it means for a multiset of premises to relevantly L-imply a multiset of conclusions, where L is a Tarskian consequence relation: the premises relevantly imply the conclusions iff there is an abstraction of the pair <premises, conclusions> such that the abstracted premises L-imply the abstracted conclusions and none of the abstracted premises or the abstracted conclusions can be omitted while still maintaining valid L-consequence.          Subsequently we apply this denition to the classical logic (CL) consequence relation to obtain NTR-consequence, i.e. the relevant CL-consequence relation in our sense, and develop a sequent calculus that is sound and complete with regard to relevant CL-consequence. We present a sound and complete sequent calculus for NTR. In a next step we add rules for an object language relevant implication to thesequent calculus. The object language implication reflects exactly the NTR-consequence relation. One can see the resulting logic NTR-> as a relevant logic in the traditional sense of the word.       By means of a translation to the relevant logic R, we show that the presented logic NTR is very close to relevance logics in the Anderson-Belnap-Dunn-Routley-Meyer tradition. However, unlike usual relevant logics, NTR is decidable for the full language, Disjunctive Syllogism (A and ~AvB relevantly imply B) and Adjunction (A and B relevantly imply A&B) are valid, and neither Modus Ponens nor the Cut rule are admissible

Reactive plasma cleaning and restoration of transition metal dichalcogenide monolayers

The cleaning of two-dimensional (2D) materials is an essential step in the fabrication of future devices, leveraging their unique physical, optical, and chemical properties. Part of these emerging 2D materials are transition metal dichalcogenides (TMDs). So far there is limited understanding of the cleaning of “monolayer” TMD materials. In this study, we report on the use of downstream H2 plasma to clean the surface of monolayer WS2 grown by MOCVD. We demonstrate that high-temperature processing is essential, allowing to maximize the removal rate of polymers and to mitigate damage caused to the WS2 in the form of sulfur vacancies. We show that low temperature in situ carbonyl sulfide (OCS) soak is an efficient way to resulfurize the material, besides high-temperature H2S annealing. The cleaning processes and mechanisms elucidated in this work are tested on back-gated field-effect transistors, confirming that transport properties of WS2 devices can be maintained by the combination of H2 plasma cleaning and OCS restoration. The low-damage plasma cleaning based on H2 and OCS is very reproducible, fast (completed in a few minutes) and uses a 300 mm industrial plasma etch system qualified for standard semiconductor pilot production. This process is, therefore, expected to enable the industrial scale-up of 2D-based devices, co-integrated with silicon technology

Causation & technical problem solving : an analysis of causal knowledge underlying proposed solutions for technical problems

In this paper we analyse the causal underpinnings of remedy claims found in technical problem solving instructions. For these claims to be successful, they need to be based on causal relations that hold in the world and that have certain properties. These required properties are the focus of our paper. We first introduce several examples from car- and bike repair manuals that demarcate our topic and function as illustrations throughout the paper. We then formulate two criteria of adequacy for problem solving manuals: the efficiency requirement and the no harm requirement. These criteria determine the required strength and properties of the causal relation, and are used to frame our analysis. We start from theories of causation by Ronald Giere and Ellery Eells to develop a series of definitions to capture the properties of the aforementioned causal relations. We conclude that remedy claims need to be based on causal relations with the following property: positive causal factorhood with weak context-unanimity. To strengthen this conclusion and situate our results in the philosophical literature on causation, we then show that other classical theories of causation (viz. David Lewis' counterfactual theory, James Woodward's interventionist theory and process theories like that of Wesley Salmon or Phil Dowe) are not adequate to capture the causal underpinnings of remedy claims. Each theory has certain properties that leads to violations of either the efficiency requirement, or the no harm requirement. We conclude with some reflections on further research