Tracks and affordances: The sources of a physical ontology

How is meaning assigned to those terms in a theory which are remote from direct observational instantiation? Models and analogies play a role, but close examination of theories in high energy physics shows that the design of experimental apparatus also influences the interpretation of such terms. Certain apparatus favours certain kinds of effects, and this affects the way mathematical theories are interpreted. In particular track producing apparatus becomes involved with theories in which photonic terms are picked out in the theory. A further conceptual constraint is thus introduced. It is argued that this situation favours the interpretation of dispositional properties as affordances rather than as simple dispositions.     

The role accorded to the public by philosophers of science 1

The role accorded to the public by scientists and philosophers of science has undergone an essential historical change in the last three centuries. Public participation in (witnessing of) scientific experiments was considered an important requirement for 17th century experimenters (e.g. for Boyle or Pascal). The cognitive role played by lay persons was later substantially downgraded; witnessing went out of fashion, while science became more and more esoteric and a matter for experts only. Part of this process was that all scientific disciplines became intensively compartmentalized and in consequence a rather puzzling or even paradoxical situation appeared: that the scientists themselves were and are being reduced epistemically to the status of lay persons, outside of their proper field of expertise (as was pointed out by J. Hardwig). The paper deals with some cognitive aspects of this historical process.     

A call for a pluralist epistemological understanding in the assessment and evaluation of counselling

The authors outline and posit the futility of the 'paradigm war' between reductionistic/positivistic and phenomenological/naturalistic philosophies within counselling evaluation, pointing out that the notion of such competition is itself based on positivist thinking. They trace attempts at creating a 'truce' in the war based on strict demarcation of territory. They conclude that in the longer term more might be gained by accepting the veracity of both philosophies and creating a pluralist model which will be more fully equipped to evaluate the human process of counselling.     

Cut-free sequent and tableau systems for propositional Diodorean modal logics

We present sound, (weakly) complete and cut-free tableau systems for the propositional normal modal logicsS4.3, S4.3.1 andS4.14. When the modality is given a temporal interpretation, these logics respectively model time as a linear dense sequence of points; as a linear discrete sequence of points; and as a branching tree where each branch is a linear discrete sequence of points.Although cut-free, the last two systems do not possess the subformula property. But for any given finite set of formulaeX the superformulae involved are always bounded by a finite set of formulaeX* _L depending only onX and the logicL. Thus each system gives a nondeterministic decision procedure for the logic in question. The completeness proofs yield deterministic decision procedures for each logic because each proof is constructive.Each tableau system has a cut-free sequent analogue proving that Gentzen's cut-elimination theorem holds for these latter systems. The techniques are due to Hintikka and Rautenberg.Presented byDov M. Gabbay     

Driving assessment with computer-video scenarios: More is sometimes better

Several factors are critical in designing effective simulator systems for driving research and driver assessment. First, there is cost, in terms of which, less is better. Costly systems are sometimes fine for specific research purposes, but they are impractical for most other purposes. Second, there is realism; in this case, more may be better, but we don’t know how much realism is really necessary for good prediction of actual driving behaviors. Recent evidence suggests that real-world clutter may enhance prediction, but it also makes interpreting research more difficult. More realism may increase cost, but this is not necessarily the case. Third, there is user-friendliness, in terms of which, again, more is better. Systems that are easier to operate require less-highly trained personnel; hence, increasing user-friendliness also decreases cost, especially for assessment. We demonstrated a highly user-friendly, low-cost, moderately realistic, and partly interactive computer-video driving research and assessment system. In recent research, we obtained multipleR values ofA7 for older drivers with only three to four scenarios predicting a real-world crash index.     

Local and global factors of similarity in visual search

Effects of the similarity between target and distractors in a visual search task were investigated in several experiments. Both familiar (numerals and letters) and unfamiliar (connected figures in a 5 × 5 matrix) stimuli were used. The observer had to report on the presence or absence of a target among a variable number of homogeneous distractors as fast and as accurately as possible. It was found that physical difference had the same clear effect on processing time far familiar and for unfamiliar stimuli: processing time decreased monotonically with increasing physical difference. Distractors unrelated to the target and those related to the target by a simple transformation (180° rotation, horizontal or vertical reflection) were also compared, while the physical difference was kept constant. For familiar stimuli, transformational relatedness increased processing time in comparison with that fort unrelated stimulus pairs. It was further shown in a scaling experiment that this effect could be accounted for by the amount of perceived similarity of the target-distractor pairs. For unfamiliar stimuli, transformational relatedness did have a smaller and less pronounced effect. Various comparable unrelated distractors resulted in a full range of processing times. Results from a similarity scaling experiment correlated well with the outcome of the experiments with unfamiliar stimuli. These results are interpreted in terms of an underlying continuum of perceived similarity as the basis of the speed of visual search, rather than a dichotomy of parallel versus serial processing.