Scientific Kinds, Knowledge, and Ontology

This dissertation stakes out a position against prevailing views on natural and scientific kinds by responding to three questions: (1) Are kinds real? (2) What are kinds like? (3) Which kinds are there? Before responding to these, I establish the significance of philosophy of kinds. Chapter 1 shows how philosophy about kinds, traditionally taken up under the heading ‘natural kinds’ but now often ‘scientific kinds’, naturally arises in core theoretical philosophical inquiries (e.g., in ontology and in dealing with the question of realism and the nature of concepts) and, conversely, how philosophical positions on kinds are simultaneously positions on other foundational philosophical issues. Chapter 2 defends a non-metaphysical realism, positioned between more popular alternatives. Metaphysical kind realism goes farther than we need to go to secure belief in our successful practices and their objects, while anti-realist theories like domain relativism, kind eliminativism, and merely epistemic accounts misconstrue and undermine our epistemic practices. My position preserves the domain independence and thus the objectivity of kinds, while rejecting that they are mind independent. Chapter 3 argues that no general theory of kinds will succeed. I show that two enduringly popular theories – essentialism and property cluster theory – fail, and argue that kinds are too diverse to admit of a general, informative treatment. Chapter 4 defends the reality of many kinds typically taken as apparent or merely conventional. Taking examples from biology, computer science, psychology, and everyday life, I show how standard approaches – what I call “restrictive” approaches – exclude indispensable kinds which obviously exist. I also show how popular permissive accounts fail: by still trying to offer a principle or account that informatively says what makes kinds real. I suggest this pursuit is destined to fail, and advocate for a novel permissive account which abandons the search for a general formula. Permissiveness fits naturally with my rejections of metaphysical realism and unified theories of kinds, which are the main motivations for restrictiveness.