compared with reflective thought, 29-31;
    science and the world as mechanism, 148;
    the conservation of energy, 151-154;
    philosophical sciences examined in detail, 223-259;
    science and metaphysical analysis, 246-247;
    the non-philosophical sciences and philosophy, 255-259;
    study of scientific principles, 256-259;
    verification in science and in philosophy, 275-277;
    philosophy as science, 281-283. 
  Scientific Knowledge:  see Science. 
  Sensations:  knowledge of things through, 33-44;
    sense and imagination contrasted, 45-49;
    are “things” groups of, 49-51;
    distinction between things and, 51-56;
    use of the word in this volume and in the
      “System of Metaphysics,” 306-307. 
  Sidgwick:  on Kant, 311. 
  Sigwart:  314. 
  Singularism and Pluralism:  described, 204-205. 
  Skeptics:  their view of philosophy, 7-8;
    their doubt of reality, 59;
    Hume’s skepticism, 171. 
  Socrates:  use of words “philosopher” and “philosophy,” 2;
    attitude toward sophism, 6. 
  Solipsism:  see Other Minds. 
  Solon:  1. 
  Sophists:  characterized, 6. 
  Soul:  see Mind. 
  Space:  plain man’s knowledge of, 73;
    said to be necessary, infinite and infinitely divisible, 73-74;
    discussion of it as necessary and as infinite, 74-77;
    Kant, Hamilton, and Spencer quoted, 75-77;
    as infinitely divisible, the moving point, 77-80;
    Clifford quoted, 79-80;
    real space and apparent, 80-87;
    “matter” and “form,” 82-84;
    extension of imaginary things, 113;
    place of mental phenomena, 115-117, also, 126-129. 
  Spencer, Herbert:  his definition of philosophy, 11;
    his work criticised, 11-12;
    on the “Unknowable” as ultimate Reality, 69-70;
    Spencer as “natural” realist, 174;
    influenced by Kant’s doctrine, 176;
    his inconsistent doctrine of the external world, 183-184;
    defective logic, 228;
    influence of agnosticism, 271;
    references given, 307, 311. 
  Spinoza:  his a priori method, 10;
    on God or substance, 199;
    his rationalism, 208;
    his parallelism, 308;
    references, 311-312. 
  Spiritualism:  the doctrine, 197-198. 
  Stoics:  their view of philosophy, 7-8; their materialism, 102. 
  Strong:  on other minds, 209; references to, 309, 311. 
  Subjective Idealism:  187-188. 
  Subjective Order:  contrasted with objective, 55. 
  Substance:  meaning of word, 108;
    Locke on, 108;
    mind as substance, 111-112;
    doctrine of the One Substance, 198-202. 
  Synthetic Judgments:  defined, 179. 
  Systems of Philosophy:  their relations to each other, 283-287.