Abstract

Huygens created his own version of the mechanical philosophy by his specification of the mechanical principles upon which natural philosophy depends, represented in De Motu Corporum ex Percussione. ;Propositions geometrically demonstrated from these mechanical foundations constitute secondary theories that are the second level of Huygens' program, represented by Traite de la Lumiere and Discours de la Cause de la Pesanteur. In the former, by adding secondary hypotheses, Huygens constructs a sequence of progressively more complex models providing an explanation for the rectilinear propagation of light. Secondary hypotheses specify and constitute matter that is the transmission medium. ;Demonstrated laws of the secondary theories, such as the Refraction Law, serve as hypotheses for the third level of Huygens' program, in which they are applied to practical purposes, such as in Dioptrica. Horologium Oscillatorium participates in all three of these explanatory levels. ;This study focuses on the upper levels of Huygens' program. The foundational impact theory of De Motu is studied in great detail. Huygens' modes of scientific explanation are outlined, including the kinds and uses of hypotheses, and Huygens' modes of theory advancement. The development of some of Huygens' foundational concepts, particularly that of perfect hardness, is traced and examined in detail, which leads naturally to an exploration of the character of idealization in Huygens' theories. The connection of the foundational theory of impact with the secondary theory of the Traite is carefully examined. The functioning of this theory in view of its mechanical foundations is also examined carefully. Finally, gravitation has seemed to some to provide conceptual difficulties for Huygens' program, so this aspect of Huygens' mechanical foundations is examined in detail. ;Huygens' work in natural philosophy represents a unified program. It is unified in its mechanical foundations. It is unified in its goal of mechanical and causal explanation of phenomena. It is unified in the modes of scientific explanation Huygens uses to attain these goals. It is needless to say that this program was not completed by Huygens. However, it is considerably more advanced than casual reading of Huygens' work or reading of the presently available secondary literature would suggest