GRE阅读笔记NO7-1.doc

NO. 7-1 Section 1 　　　Our visual perception depends on SE 　　the reception of energy reflecting or 　　radiating from that which we wish to 　　perceive. If our eyes could receive and (5) measure infinitely delicate sense-data, 　　we could perceive the world with 　　infinite precision. The natural limits 　　of our eyes have, of course, been 　　extended by mechanical instruments; (10) telescopes and microscopes, for example, 　　expand our capabilities greatly. There TS 　　is, however, an ultimate limit beyond 指示词 　　which no instrument can take us; this 　　limit is imposed by our inability to (15) receive sense-data smaller than those ﹤ 　　conveyed by an individual quantum of 　　energy. Since these quanta are believed 指示词 　　to be indivisible packages of energy 　　and so cannot be further refined, we (20) reach a point beyond which further 　　resolution of the world is not possible. 　　It is like a drawing a child might make 　　by sticking indivisible discs of color 　　onto a canvas. (25) 　We might think that we could avoid 　　this limitation by using quanta with 　　extremely long wavelengths; such quanta 　　would be sufficiently sensitive to 　　convey extremely delicate sense-data. (30) And these quanta would be useful, 　　as long as we only wanted to measure ⊙ 　　energy, but a completely accurate SE 指示词— 　　perception of the world will depend also 　　on the exact measurement of the lengths (35) and positions of what we wish to 　　perceive. For this, quanta of extremely 　　long wavelengths are useless. To 　　measure a length accurately to within a 　　millionth of an inch, we must have a (40) measure graduated in millionths of an 　　inch; a yardstick graduated in inches is 　　useless. Quanta with a wavelength of one 　　inch would be, in a sense, measures 　　that are graduated in inches. Quanta of (45) extremely long wavelength are useless in 　　measuring anythin