-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.

Taylor: on other minds, 309.
Teleology: what, 163; reference, 310.
"Telephone Exchange": doctrine of the external world
as "messages," 38-44.
Thales: his doctrine, 3.
Theism: see God.
Theory of Knowledge: see Epistemology.
Things: our knowledge of, 18-23;
contrast of ideas and, 33-36