Whewell posited certain “Fundamental Ideas,” such as Space, Time, Cause, and Resemblance, which enabled “unconscious inference” so that we could structure and relate our sensations in ways that resulted in our perceptions of objects. He thought that each science has a distinct Particular Fundamental Idea that makes sense of its subject matter: For instance, the idea of Space for geometry, Cause for mechanics, and Substance for chemistry. The fundamental idea of a science can be further modified to fit the requirements of that science, such as the idea of force as a modification of the idea of Cause in mechanics.