View Single Post
Old 03-02-2006, 11:33 PM   #18 (permalink)
noahfor
Addict
 
Here is my essay on the Kant, if anyone cares. It's not good either, but I had a hard time understanding the relationship between non-Euclidean geometries and Kant that would make the geometries existence undermine Kant. I don't really even think they do.

Propositions can be either analytic or synthetic. An analytic proposition is one whose truth is contained within the meaning of its parts, and states nothing more than its parts alone. For instance, “If A then A” is true because states nothing more than “If A,” and so it is analytic. An analytic proposition is necessarily true. A synthetic proposition is one that states more than its parts alone. For instance, “If A then B” cannot be known by reference to its parts because nothing of A’s relationship with B is contained within A, and so it is synthetic. As well, proposition can be either a priori or a posteriori. A proposition is a priori if its truth does not depend on experience. A proposition is a posteriori if its truth can only be concluded by reference to experience.
There are four possible combinations of the types of propositions: analytic a priori, analytic a posteriori, synthetic a priori, and synthetic a posteriori. Analytic a priori propositions are possible because, by definition of an analytic proposition, their truth is necessitated by the meaning of their parts and not by any connection to experience. For the same reason analytic a posteriori propositions are not possible. From common experience we know that synthetic a posteriori propositions are possible. That leaves one last possible combination, synthetic a priori. Kant claims that not only are synthetic a priori propositions possible, but that they are also the basis for all of mathematics and natural science.
Kant believes that all perceptions must take place within space and time, but that the sense data which supplies the material for perception does not contain any information about its existing in space and time. Instead, Kant believes that space and time are structures that are added to perception in order to facilitate our understanding of sense data, and that space and time are understood a priori. Kant calls space and time intuitions. He argues that synthetic propositions can be made whose truth can be verified by reference only to space and time, and since space and time are understood a priori, these propositions will also be a priori. For instance, “Space has three dimensions.” can be verified by our understanding of space, and is synthetic because there is nothing of three-dimensionality inherent in the concept of space. It is Kant’s belief that all mathematical and geometrical propositions are synthetic a priori propositions generated and verified in this manner.
Of the synthetic a priori propositions based on the spatial intuition, were Euclid’s postulates, on which all of Euclidean geometry is based. However, in the 1800’s geometers began experimenting with geometries in which Euclid’s fifth postulate – “If two lines are drawn which intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough” – is excluded. They found that by proposing a space shaped like a sphere, defining a line as great circle around the surface of the sphere, and a point as two opposite points on the sphere, they could create consistent geometries in which there are no parallel lines.
In Kant’s view it is our understanding of space that provides the basis for geometrical synthetic a priori propositions, such as Euclid’s fifth postulate, and it is the a priori nature of the spatial intuition that makes propositions based on it a priori, and a proposition derived from a non-Euclidean geometry, such as “no parallel lines are possible” can be seen as being of the same sort to propositions that are Euclidean in nature, except for the space that they describe. However, in the case of non-Euclidean propositions, the positions are not based on our intuitive space, but are also not based on any experienced space, so they must be analytically true. Thus, due to their equivalency to non-Euclidean propositions, Euclidean propositions must also be analytic in nature.
Kant also proposes that synthetic a priori propositions are the basis for the natural sciences. These, however, are not based on the intuitions, but on something he calls Categories. The Categories are to propositions what the intuitions are to perceptions, and that is the extent to which I understand them. From the categories, Kant believes propositions such as “Every happening has a cause.” can be known. It is on statements like this one that Newtonian physics is based. However, with the development of quantum mechanics we have learned that some happenings do not have a cause. For instance, the decay of an atomic nucleus happens completely by chance, and even if all the physical circumstances surrounding the nucleus of an atomic known, one could still not predict with certainty whether, at a given time, it would decay or not. Thus, Kant’s proposition “Every happening has a cause.” is falsified. Hence, it was never known, and whatever method used in obtaining the supposed knowledge failed to obtain any knowledge at all.

Thanks to everyone that helped me out.

Last edited by noahfor; 03-02-2006 at 11:36 PM..
noahfor is offline  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360