Instant, 33, 35, 57 Instantaneous plane, 91; present, 72; spaces, 86, 90, 177 Instantaneousness, 56, 57 Intersection, locus of, 90 Intrinsic character, 80, 82, 90, 113, 191; properties, 62 Ionian thinkers, 19 Irrelevance, infinitude of, 12 Irrevocableness, 35, 37 It, 8 Julius Caesar, 36 Junction, 76, 101 Kinetic energy, 105; symmetry, 129 Knowledge, 28, 32 Lagrange, 140 Larmor, 131 Law of convergence, 82 Laws of motion, 137, 139; of nature, 196 Leibnizian monadology, 150 Level, 91, 92 Light, 195; ray of, 188; velocity of, 131 Limit, 57 Limited events, 74 Location, 160, 161 Locke, 27 Locus, 102; of intersection, 90 London, 97 Lorentz, H. A., 131, 133 Lossky, 47 Manifold, four-dimensional, 86; space-time, 173 Material ether, 78; object, 169 Materialism, 43, 70 Matrix, 116 Matter, 16, 17, 19, 20, 26 Maxwell, 131, 133 Measurableness, 196; of nature, 193 Measurement, 96, 120, 174, 196; of time, 65, 140 Measure-system, 196 Memory, 68 Metaphysics, 28, 32 Metrical geometry, 129 Michelson-Morley, 195 Milton, 35 Mind, 27, 28 Minkowski, viii, 131 Molecule, 32, 171 Moment, 57, 60, 88 Momental area, 103; route, 103 Momentum, 105 Motion, 105, 114, 117, 127, 188, 192 Multiplicity, 22 Natural philosophy, 29, 30 Natural science, philosophy of, 46 Nature, 3; apparent, 31, 39; causal, 31, 39; conceptual, 45; continuity of, 59, 76; discrimination of, 144; extended, 196; laws of, 196; passage of, 54; stratification of, 194, 196; system of, 146 Newton, 27, 136, 139, 140 Object, 77, 125, 143, 169, 189; delusive perceptual, 155; material, 169; perceptual, 153; physical, 155, 157; scientific, 158, 169; uniform, 162 Occupation, 22, 34, 36, 100, 101 Order, source of, 192; spatial, 95, 194; temporal, 64, 95, 194 Organisation of thought, 79 Outside, 63, 100 Paradox, 192 Parallel, 63, 127; durations, 190 Parallelism, 95, 191 Parallelogram, 127 Paris, 87, 138 Parliament, 120 Part, 14, 15, 58 Passage of events, 34; of nature, 54 Past, the, 72, 177 Perception, 3 Perceptual objects, 149, 153 Percipience, 28 Percipient event, 107, 152, 186, 187 Period of time, 51 Permanence, 144 Perpendicularity, 117, 127, 193 Philosophy, 1; natural, 29, 30; of natural science, 46; of the sciences, 2 Physical field, 190; object, 155, 156, 157 Physics, speculative, 30 Place, 51 Plane, 191; instantaneous, 91 Plato, 16, 17, 18, 24, 197 Poincaré, 121, 122, 123 Point, 35, 89, 91, 114, 173, 176 Point-flash, 172, 173 Point of space, 85 Point, timeless, 192 Point-track, 113, 198 Pompey, 36 Position, 89, 90, 92, 93, 99, 113, 191; absolute, 105, 106, 114, 188