Synaesthesia is a condition in which one type of stimulation evokes the sensation of another, as when the hearing of a sound produces photisms, i.e. mental percepts of colours. R is a 20 year old colour blind subject who, in addition to the relatively common grapheme-colour synaesthesia, presents a rarely reported cross modal perception in which a variety of visual stimuli elicit aura-like percepts of colour. In R, photisms seem to be closely related to the affective valence of stimuli and (...) typically bring out a consistent pattern of emotional responses. The present case study suggests that colours might be an intrinsic category of the human brain. We developed an empirical methodology that allowed us to study the subject's otherwise inaccessible phenomenological experience. First, we found that R shows a Stroop effect elicited by photisms despite the fact that he does not show a regular Stroop with real colours. Secondly, by manipulating the colour context we confirmed that colours can alter R's emotional evaluation of the stimuli. Furthermore, we demonstrated that R's auras may actually lead to a partially inverted emotional spectrum where certain stimuli bring out emotional reactions opposite to the normal ones. These findings can only be accounted for by considering R's subjective colour experience or qualia. Therefore the present paper defends the view that qualia are a useful scientific concept that can be approached and studied by experimental methods. (shrink)

The Birkhoff-Maltsev problem asks for a characterization of those lattices each of which is isomorphic to the lattice L(K) of all subquasivarieties for some quasivariety K of algebraic systems. The current status of this problem, which is still open, is discussed. Various unsolved questions that are related to the Birkhoff-Maltsev problem are also considered, including ones that stem from the theory of propositional logics.

We assume, in the first place, that two kinds of processes occur in nature: the strictly continuous and causal ones, which are governed by the Schrödinger equation and those implying discontinuities, which are ruled by probability laws. In the second place, we adopt a postulate ensuring the statistical sense of conservation laws. These hypotheses allow us to state a rule telling, in principle, in which situations and to which vectors the system's state can collapse, and which are the corresponding probabilities. (...) The way our proposed approach works is illustrated with some examples and with the analysis of the measurement problem. We obtain the exponential decay law. A comparison with other attempts to solve the measurement problem is performed. (shrink)

LetL(K) denote the lattice (ordered by inclusion) of quasivarieties contained in a quasivarietyK and letD 2 denote the variety of distributive (0, 1)-lattices with 2 additional nullary operations. In the present paperL(D 2) is described. As a consequence, ifM+N stands for the lattice join of the quasivarietiesM andN, then minimal quasivarietiesV 0,V 1, andV 2 are given each of which is generated by a 2-element algebra and such that the latticeL(V 0+V1), though infinite, still admits an easy and nice description (...) (see Figure 2) while the latticeL(V 0+V1+V2), because of its intricate inner structure, does not. In particular, it is shown thatL(V 0+V1+V2) contains as a sublattice the ideal lattice of a free lattice with free generators. Each of the quasivarietiesV 0,V 1, andV 2 is generated by a 2-element algebra inD 2. (shrink)

How ought Christians to approach moral problems? This is a question of method in moral theology. It is also a question of who is in authority to speak on matters of morality. In this essay, the moral methodology of Richard McCormick, S.J., one of the most powerful voices in contemporary Roman Catholic theology, is explored in depth. Attention is focused on its critical details, its development over time, and in particular McCormick's use of authorities in Roman Catholicism. It is argued (...) that his ethical theory is built around one central insight: that the human person in all its facets and dimensions is the criterion of the rightness and wrongness of human actions. (shrink)