In the Optics, Descartes claims that telescopes and microscopes lead to morally certain knowledge. It is unclear, however, that Descartes’s expressed confidence in these instruments is warranted. In this article, I show how a limited range of telescope and microscope observations could lead to morally certain knowledge for Descartes, and how observations beyond this range admit of enough reasonable doubt to undermine moral certainty. I also explain moral certainty as a form of knowledge in Descartes’s scientific practices, his epistemic commitment to optical instruments, and I offer an explanation for why Descartes never used optical instruments in his scientific endeavours.

Hegel has a metacritical standpoint that can be related to but not reduced to the Herderian metacritique. Hegel’s philosophical language must not be understood in terms of the opposition between an ‘absolute’ and a ‘finite’ language; rather, it must be understood in terms of the opposition between abstract and concrete language. At a theoretical level, concrete language cannot be understood without assuming an organic function of memory. At the practical level, the difference between abstract and concrete language will be understood as the difference between everyday language and a philosophical one. Hegel justifies this last difference by following Humboldtian standpoints.

This paper explores the idea of robust discursive equality on which respect-based conceptions of justificatory reciprocity often draw. I distinguish between formal and substantive discursive equality and argue that if justificatory reciprocity requires that people be accorded formally equal discursive standing, robust discursive equality should not be construed as requiring standing that is equal substantively, or in terms of its discursive purchase. Still, robust discursive equality is purchase sensitive: it does not obtain when discursive standing is impermissibly unequal in purchase. I then showcase different candidate conceptions of purchase justice, and draw conclusions about the substantive commitments of justificatory reciprocity.

In Mind and World, John McDowell claims that we need to steer our way between bald naturalism and rampant platonism as two ways to explain our capacity to use concepts. Performing this task requires an explanation of how concepts can be both socially charged and, at the same time, genuinely involving the world as it really is. I suggest that McDowell’s explanation is insufficient and that Wilfrid Sellars’s idea of sense impressions might be used to clarify the relationship between social practices and conceptual knowledge without incurring too much damage to the overall architectonics of McDowell’s theory.

According to the dispositional theory of meaning and content, what a speaker means by an expression is determined by her dispositions to use it. The literature contains two well-known objections against this theory: the problem of finitude and the problem of error. In his book Meaning and Normativity, Allan Gibbard propounds a novel defence against these objections. In this paper, I argue that Gibbard’s suggestions fail to save the dispositional theory. Moreover, I argue that Gibbard’s deflationary view about facts prevents him from saying anything about the property of meaning that would hold any interest for a naturalist.

Locke’s property rights are now usually understood to be both fundamental and strictly negative. Fundamental because they are thought to be basic constraints on what we may do, unconstrained by anything deeper. Negative because they are thought to only protect a property holder against the claims of others. Here, I argue that this widespread interpretation is mistaken. For Locke, property rights are constrained by the deeper ‘fundamental law of nature,’ which involves positive obligations to those in need and confines the right to excess property within circumstances where it is not needed to preserve human life.

Maximizing Hedonism maintains that the most pleasurable pleasures are the best. Francis Bradley argues that this is either incompatible with Mill’s Qualitative Hedonism, or renders the latter redundant. Some ‘sympathetic’ interpreters respond that Mill was either a Non-Maximizing Hedonist or a Non-Hedonist. However, Bradley’s argument is fallacious, and these ‘sympathetic’ interpretations cannot provide adequate accounts of: Mill’s identification with the Protagorean Socrates; his criticisms of the Gorgian Socrates; or his apparent belief that Callicles is misguided to attempt to show that the pleasures of the intelligent can be more valuable than the pleasures of fools without also being more pleasurable.