登陆注册
15446100000031

第31章 PURE SENSATIONS(14)

Sometimes they indiscriminately translate the results of physical color-mixing into physiological processes, as in the assumption of three fundamental colors, red, green, and violet, from the different mixtures of which all sensations of light, even the achromatic, are to be derived (Young-Helmholtz hypothesis). Sometimes they start with the psychologically untenable assumption that the naming of colors is not due to the influence of certain external objects, but to the real significance of the corresponding sensations (v. sup. p. 63), and assume accordingly four fundamental colors as the sources of all color-sensations. The four fundamental colors here assumed are the two pairs red and green, yellow and blue, to which are added the similar pair of sensations of pure brightness, black and white. All other light-sensations such as grey, orange, violet, etc., are regarded as subjectively and objectively mixed colors (Hering's hypothesis). The evidence in support of the first as of the second of these hypotheses has been derived for the most part from the riot infrequent cases of partial color-blindness. Those who accept three fundamental colors, assert that all these cases are to be explained as a lack of the red or green sensations, or else as a lack of both. Those who accept four, hold that partial color-blindness always includes two fundamental colors that belong together as opposites, and is, therefore, either [p. 73] red-green-blindness or yellow-blue-blindness.

An unprejudiced examination of color-blindness does not justify either of these assertions. The three-color theory can not explain total color blindness, and the four-color theory is in contradiction to cases of pure red-blindness and pure green-blindness. Finally, both theories are overthrown by the cases that unquestionably occur, in which such parts of the spectrum as do not correspond to any of the three or four fundamental colors, appear colorless. The only thing that our present knowledge justifies us in saying, is that every simple sensation of light is conditioned physiologically by a combination of two photochemical processes, a monochromatic and a chromatic. The first is made up, in turn, of a process mainly of disintegration, when the light is more intense, and a process of restitution, when the light is weaker. The chromatic process varies by stages in such a way that the whole series of photochemical color-disintegrations forms a circle of processes in which the products of the disintegration for any two relatively most distant stages, neutralize each other. [ 6 ]

Various changes as a result of the action of light have been observed in the living retina, all of which go to support the assumption of a photochemical process. Such are the gradual change into a colorless state, of a substance which in the retina not exposed to light is red (bleaching of the visual purple); microscopical movements of the pigmented protoplasm between the sensitive elements, or rods and cones; and, finally, changes in the form of the rods and cones themselves. Attempts to use these phenomena in any way for a physiological theory of light stimulation, are certainly premature.

The most probable conclusion which we can now draw is that the difference in the [p. 74] forms of the rods and cones is connected with a difference in function. The centre of the retina, which is the region of direct vision in the human eye, has only cones, while in the eccentric parts the rods are more numerous; furthermore, in the centre (which also wants the visual purple) the discrimination of colors is much better than in the eccentric regions, while the latter are much more sensitive to brightness. The natural conclusion from these facts is that the differences in sensitivity are connected with the photochemical properties of the rods and cones. Still, we lack here too any particular evidence.

[ 1] Pendulum-oscillations may be represented by a sine-curve, because the distance from the position of rest is always proportional to the sine of the time required to swing to the point in question.

[ 2] It must be observed, however, that the actual coincidence of these sensations can be empirically proved only for the minimum of brightness.

Grades of brightness which approach the maximum are so injurious to the eye that the general demonstration of the approach to white must be accepted as sufficient.

[ 3] The same false reasoning from the names of sensations, has even led some scholars to assume that the sensation blue developed later than other color-sensations, because, for example, even in Homer the word for blue is the same as that for "dark". Tests of the color-sensations of uncivilized peoples whose languages are much more deficient in names for colors than that of the Greeks at the time of Homer, have given us a superabundance of evidence that this assumption is utterly without ground.

[ 4] Many physicists, to be sure, believe that an analogous relation is to be found between tones of different pitch, in the fact that every tone has in its octave a similar tone. But this similarity, as we shall see (§ 9), does not exist between simple tones, but depends on the actual sympathetic vibration of the octave in all compound clangs.

Attempts to support this supposed analogy by finding in the color-line intervals corresponding to the various tonal intervals, third, fourth, fifth, etc., have all been entirely futile.

[ 5] In the neighborhood of green this advantage does not exist, and the mixtures always appear less saturated than the intermediate simple colors. This is a clear proof that the choice of the three fundamental colors mentioned is indeed the most practical, but nevertheless arbitrary, and at bottom due to the familiar geometrical principle that a triangle is the simplest figure that can enclose a finite number of points in the same plane.

[ 6] The further assumption is made by the defenders of the four fundamental colors, that two opposite colors are related just as bright and dark achromatic stimulations, that is, that one of these colors is due to a photochemical disintegration (dissimilation), the other to a restitution (assimilation). This is an analogy that contradicts the actual facts. The result obtained by mixing complementary colors is on its subjective side a suppression of the color-sensation, while the mixture of white and black, on the other band, produces an intermediate sensation.

同类推荐
热门推荐
  • 会有人陪你走过漫漫长路

    会有人陪你走过漫漫长路

    初恋,就像一颗未成熟的青梅,青涩中夹杂着酸与微甜,当女孩文梓遇到那个大男孩,便已埋下了一颗懵懂的种子,想要和他亲近,想要和他成为朋友。从初始他的隐隐心动到熟知你的沾沾自喜,种子渐渐萌发成芽。悸动的青春,是喜欢上了吗?文梓并不清楚,她只知道她已习惯追随着他,习惯了他摸她的头,习惯了每天午睡后看见的那张睡颜,习惯了他的青草香,习惯了他调侃自己胖。可是他们仍旧敌不过岁月的洗礼,别了,我的大男孩!471450703,这是群号,喜欢的可以加进来哟!么么哒!
  • 风与水的传说

    风与水的传说

    本书以男猪脚风辰一生的传奇经历为主线,共分少年,学院,战争,流浪,天下五个部分,是一个集魔幻,冒险,爱情,战争,游戏,人生为一体的异世故事。
  • 漱溟

    漱溟

    上善若水,水善利万物而不争,处众人之所恶,故几于道。
  • 末日培养计划

    末日培养计划

    三个月的游戏经验,一只死亡重启时间的计时手环。对于张陌而言,这是一场末日,也是一场“游戏”。唯一的区别在于,存档重来的时候有点疼。嗯,对,就是这样。
  • 混沌界子

    混沌界子

    大夏二皇子钟昊被未婚妻和大哥毒杀,重生到十年之后,成为步家废物步浩.......“既然我钟昊能够重生,那便是天不绝我,十年之后,当我再次站在你们面前时,便是你们体会这种绝望的噩梦之时。”用心之作,放心入坑,包填包埋。
  • 嗜血鬼猎人

    嗜血鬼猎人

    22世纪,中国秦始皇的陵墓被打开,这位伟大的君王开创了中国的新的历史。几千年后又给人类翻开了新的一页。镇守古墓的是人们从未想象过的恐怖生物,又或者说是死物——嗜血鬼。打扰帝王安睡者将受到来自地狱的惩罚。于是人类迎来新的挑战,打倒嗜血鬼成为了人类的目标。一个少年在这严酷的世界生存着,成长着。期间他遇见了很多人,在这乱世之中,每一个都用自己的方式为自己和人类战斗着,迎接他们的将会是怎样的未来?
  • 异界逍遥成圣

    异界逍遥成圣

    在传统武学逐渐没落的现代社会,逍遥派弟子李天桥在一次海难中穿越到了异世界。在这个剑与魔法的世界,他惊异地发现这里也有炎黄子孙,而这个世界的炎黄族,却世代相传着一个惊天的大秘密。看李天桥如何利用自己掌握的知识和武功与异界的敌人斗智斗勇,看逍遥派和中华传统武学如何在异界发扬光大……
  • 血色长夜

    血色长夜

    迷人的城市之夜,是灯红酒绿的天堂,还是血染的恐怖地狱?白色的长裙,转身却是滴血的容颜。是单纯的少女,还是可怕的吸血鬼?一切的谜团,看稚嫩的少年如何解开。到了最后的最后,理智与感性的交锋之时,又该如何抉择!
  • 无上至尊经

    无上至尊经

    百万年前,轮回天门现世。十万年,天魂道经流出,被称为《无上至尊经》,此后每万年此经都会现世,掀起腥风血雨。冷锋,万剑门曾经的少年天才,携带《天魂道经》意外重生……
  • 再现轩辕

    再现轩辕

    "Fire!"随着某国长官一声令下,地球各国之间开始了一场罪恶的核战争在经历辐射、炮火洗礼之后,地球,这位人类的母亲开始展现出它所不为人知的一面柳山河面对这个满目疮痍的世界如何一步步走上巅峰然而,这只是开始...