Philosophical instruments were designed to examine phenomena experimentally, rather than by naturalistic observation alone. In the nineteenth century, some instruments were called philosophical toys because they provided popular amusement as well as experimental assistance. This book is designed to explain the technical ideas that are taken for granted in much contemporary philosophical writing. Notions like 'denumerability', 'modal scope distinction', 'Bayesian conditionalization', and 'logical completeness' are usually only elucidated deep within difficult specialist texts. By offering simple explanations that by-pass much irrelevant and boring detail, Philosophical Devices is able to cover a wealth of material that is normally only available to specialists. new in excellent condition NWOT