Sortal concepts are at the center of certain logical discussions and have played a significant role in solutions to particular problems in philosophy. Apart from logic and philosophy, the study of sortal concepts has found its place in specific fields of psychology, such as the theory of infant cognitive development and the theory of human perception. In this monograph, different formal logics for sortal concepts and sortal-related logical notions are characterized. Most of these logics are intensional in nature and possess, (...) in addition, a bidimensional character. That is, they simultaneously represent two different logical dimensions. In most cases, the dimensions are those of time and natural necessity, and, in other cases, those of time and epistemic necessity. Another feature of the logics in question concerns second-order quantification over sortal concepts, a logical notion that is also represented in the logics. Some of the logics adopt a constant domain interpretation, others a varying domain interpretation of such quantification. Two of the above bidimensional logics are philosophically grounded on predication sortalism, that is, on the philosophical view that predication necessarily requires sortal concepts. Another bidimensional logic constitutes a logic for complex sortal predicates. These three sorts of logics are among the important novelties of this work since logics with similar features have not been developed up to now, and they might be instrumental for the solution of philosophically significant problems regarding sortal predicates. The book assumes a modern variant of conceptualism as a philosophical background. For this reason, the approach to sortal predicates is in terms of sortal concepts. Concepts, in general, are here understood as intersubjective realizable cognitive capacities. The proper features of sortal concepts are determined by an analysis of the main features of sortal predicates. Posterior to this analysis, the sortal-related logical notions represented in the above logics are discussed. There is also a discussion on the extent to which the set-theoretic formal semantic systems of the book capture different aspects of the conceptualist approach to sortals. These different semantic frameworks are also related to realist and nominalist approaches to sortal predicates, and possible modifications to them are considered that might represent those alternative approaches. (shrink)

Locke defines knowledge as the perception of the agreement or disagreement of ideas. Nevertheless, he claims that we know particular things: the identity of our ideas, our own existence, and the existence of external objects. Although much has been done to reconcile the definition of knowledge with our knowledge of external objects, there is virtually nothing in the scholarship when it comes to knowing ideas or our own existence. I fill in this gap by arguing that perceptions of ideas are (...) complex mental states that convey propositional knowledge due to agreeing elements therein. (shrink)

Locke’s remarks about attention have not received a great deal of attention from commentators. In Section 1, I make the case that attention plays an important role in his philosophy. In Section 2, I describe and discuss five Lockean claims about attention. In Section 3, I explore Locke’s views about attention in relation to his account of sense perception. He thinks that we attend to objects by attending to ideas, and I argue that he treats sensory ideas as transparent in (...) a particular sense. In Section 4, I raise the worry that some of Locke’s remarks about attention seem at odds with his doctrine of the transparency of the mind. I offer two ways of resolving the problem, and suggest that they are parts of a single story. (shrink)

Ideas play at least two roles in Locke's theory of the understanding. They are constituents of ‘propositions,’ and some of them ‘represent’ the qualities and sorts of surrounding bodies. I argue that each role involves a distinct kind of intentional directedness. The same idea will in general be an ‘idea of’ two different objects, in different senses of the expression. Identifying Locke's scheme of twofold ‘ofness’ reveals a common structure to his accounts of simple ideas and complex ideas of substances. (...) A consequence is a distinction among substance sorts parallel to one of his distinctions between primary and secondary qualities. (shrink)

(2009). The Role of Natural Philosophy in the Development of Locke's Empiricism. British Journal for the History of Philosophy: Vol. 17, No. 1, pp. 55-83.

This thesis investigates Hume’s philosophy of external existence in relation to, and within the context of, his philosophy of scepticism. In his two main works on metaphysics – A Treatise of Human Nature (1739–40) and the first Enquiry (first ed. 1748) – Hume encounters a predicament pertaining to the unreflective, ‘vulgar’ attribution of external existence to mental perceptions and the ‘philosophical’ distinction between perceptions and objects. I argue that we should understand this predicament as follows: the vulgar opinion is our (...) natural and default belief for Hume, but causal reasoning reveals it to be false, and the philosophical alternative is a confabulation that we cannot permanently believe and is devoid of justification. Hume uses the fact that we cannot have a satisfactory account of belief in external existence as a sceptical consideration to motivate his wider philosophical scepticism. Hume’s response to his predicament about external existence is found in the context of his confrontation with other sceptical worries (Treatise 1.4.7 and Enquiry 12), in which Hume also reflects generally on the nature and implications of scepticism. I argue that we should characterise Hume’s position as residually sceptical. This means that, while Hume accepts the unanswerability of some sceptical problems, he denies that it is possible to eradicate all belief as a result (and denies that it is practically useful to even try) and instead uses sceptical problems as a motivation to adopt a moderately sceptical position. While we inevitably return to entertaining the vulgar belief, there is no solution to the sceptical predicament; Hume does not endorse the vulgar belief, or the philosophical system, or indeed any alternative system of the external world that might extinguish the predicament. Sceptical doubt, for Hume, does not derail intellectual pursuits, but rather modifies our attitudes in those very pursuits. (shrink)

In Philosophy and the Mirror of Nature (1979), Richard Rorty locates the perceived ills of modern philosophy in the "epistemological turn" of Descartes and Locke. This chapter argues that Rorty's accounts of Descartes' and Locke's philosophical work are seriously flawed. Rorty misunderstood the participation of early modern philosophers in the rise of modern science, and he misdescribed their examination of cognition as psychological rather than epistemological. His diagnostic efforts were thereby undermined, and he missed Descartes' original conception of a general (...) physics, and Locke's probabilist analysis of the grounds for rational belief. (shrink)