Metaphysical and Conceptual Grounding

Recently, many philosophers have claimed that the world has an ordered, hierarchical structure, where entities at lower ontological levels are said to metaphysically ground entities at higher ontological levels. Other philosophers have recently claimed that our language has an ordered, hierarchical structure. Semantically primitive sentences are said to conceptually ground less primitive sentences. It’s often emphasized that metaphysical grounding is a relation between things out in the world, not a relation between our sentences. But conflating these relations is easy to do, given that both types of grounding are expressed by non-causal “in-virtue-of” claims. The purpose of this paper is to clarify the relation between metaphysical and conceptual grounding. I argue that conceptual and metaphysical grounding are exclusive: if a given in-virtue-of claim involves conceptual grounding, then it does not involve metaphysical grounding. I also develop some heuristics for deciding which type of grounding is relevant in a given case. These heuristics suggest that many proposed cases of metaphysical grounding do not actually involve metaphysical grounding at all

Structural Relativity and Informal Rigour

Informal rigour is the process by which we come to understand particular mathematical structures and then manifest this rigour through axiomatisations. Structural relativity is the idea that the kinds of structures we isolate are dependent upon the logic we employ. We bring together these ideas by considering the level of informal rigour exhibited by our set-theoretic discourse, and argue that different foundational programmes should countenance different underlying logics (intermediate between first- and second-order) for formulating set theory. By bringing considerations of perturbations in modal space to bear on the debate, we will suggest that a promising option for representing current set-theoretic thought is given by formulating set theory using quasi-weak second-order logic. These observations indicate that the usual division of structures into \particular (e.g. the natural number structure) and general (e.g. the group structure) is perhaps too coarse grained; we should also make a distinction between intentionally and unintentionally general structures

A Statistical Study of Wages, Prices and Employment in the. Irish Manufacturing Sector. General Research Series Paper No. 29, January 1966

This paper is concerned with the estimation of certain economic relationships in the Irish economy. It seems important that attempts be made to put figures on relationships believed to exist (for instance between the level of unemployment and annual changes in earnings) rather than to speculate on these relationships. This study tries to do this but it is important to emphasise that this is an exercise in statistics and that the statements made about these relationships are essentially probability statements. This means that the degree of certainty attached to any set of figures in this study is far from being of the same order as found in, say, calculations of future eclipses. As it would be tedious to repeat this qualification at almost every step in the paper the author trusts it will be borne in mind. The figures we get may be more usefully regarded as fairly reliable orders of magnitude. This study was completed in the summer vacation of 1964 and the author realises only too dearly that it is an exploratory venture and as such cannot be expected to provide complete answers on the topics covered. But it is hoped that it provides a useful starting point for further studies

Bio-inspired swing leg control for spring-mass robots running on ground with unexpected height disturbance

We proposed three swing leg control policies for spring-mass running robots, inspired by experimental data from our recent collaborative work on ground running birds. Previous investigations suggest that animals may prioritize injury avoidance and/or efficiency as their objective function during running rather than maintaining limit-cycle stability. Therefore, in this study we targeted structural capacity (maximum leg force to avoid damage) and efficiency as the main goals for our control policies, since these objective functions are crucial to reduce motor size and structure weight. Each proposed policy controls the leg angle as a function of time during flight phase such that its objective function during the subsequent stance phase is regulated. The three objective functions that are regulated in the control policies are (i) the leg peak force, (ii) the axial impulse, and (iii) the leg actuator work. It should be noted that each control policy regulates one single objective function. Surprisingly, all three swing leg control policies result in nearly identical subsequent stance phase dynamics. This implies that the implementation of any of the proposed control policies would satisfy both goals (damage avoidance and efficiency) at once. Furthermore, all three control policies require a surprisingly simple leg angle adjustment: leg retraction with constant angular acceleration

Steps toward accurate large-area analyses of Genesis solar wind samples: evaluation of surface cleaning methods using total reflection X-ray fluorescence spectrometry

Total reflection X-ray fluorescence spectrometry (TXRF) was used to analyze residual surface contamination on Genesis solar wind samples and to evaluate different cleaning methods. To gauge the suitability of a cleaning method, two samples were analyzed following cleaning by lab-based TXRF. The analysis comprised an overview and a crude manual mapping of the samples by orienting them with respect to the incident X-ray beam in such a way that different regions were covered. The results show that cleaning with concentrated hydrochloric acid and a combination of hydrochloric acid and hydrofluoric acid decreased persistent inorganic contaminants substantially on one sample. The application of CO2 snow for surface cleaning tested on the other sample appears to be effective in removing one persistent Genesis contaminant, namely germanium. Unfortunately, the TXRF analysis results of the second sample were impacted by relatively high background contamination. This was mostly due to the relatively small sample size and that the solar wind collector was already mounted with silver glue for resonance ion mass spectrometry (RIMS) on an aluminium stub. Further studies are planned to eliminate this problem. In an effort to identify the location of very persistent contaminants, selected samples were also subjected to environmental scanning electron microscopy. The results showed excellent agreement with TXRF analysis