Unit Three:Why Do We Believe That the Earth Is Round

Can you prove that the earth is round? Go ahead and try! Will you rely on your senses or will you have to draw on the opinions of experts?
WHY DO WE BELIEVE
THAT THE EARTH IS ROUND?

George Orwell
Somewhere or other — I think it is in the preface to saint Joan — Bernard Shaw remarks that we are more gullible and superstitious today than we were in the Middle Ages, and as an example of modern credulity he cites the widespread belief that the earth is round. The average man, says Shaw, can advance not a single reason for thinking that the earth is round. He merely swallows this theory because there is something about it that appeals to the twentieth-century mentality.
Now, Shaw is exaggerating, but there is something in what he says, and the question is worth following up, for the sake of the light it throws on modern knowledge. Just why do we believe that the earth is round? I am not speaking of the few thousand astronomers, geographers and so forth who could give ocular proof, or have a theoretical knowledge of the proof, but of the ordinary newspaper-reading citizen, such as you or me.
As for the Flat Earth theory, I believe I could refute it. If you stand by the seashore on a clear day, you can see the masts and funnels of invisible ships passing along the horizon. This phenomenon can only be explained by assuming that the earth's surface is curved. But it does not follow that the earth is spherical. Imagine another theory called the Oval Earth theory, which claims that the earth is shaped like an egg. What can I say against it?
Against the Oval Earth man, the first card I can play is the analogy of the sun and moon. The Oval Earth man promptly answers that I don't know, by my own observation, that those bodies are spherical. I only know that they are round, and they may perfectly well be flat discs. I have no answer to that one. Besides, he goes on, what reason have I for thinking that the earth must be the same shape as the sun and moon? I can't answer that one either.
My second card is the earth's shadow: When cast on the moon during eclipses, it appears to be the shadow of a round object. But how do I know, demands the Oval Earth man, that eclipses of the moon are caused by the shadow of the earth? The answer is that I don't know, but have taken this piece of information blindly from newspaper articles and science booklets.
Defeated in the minor exchanges, I now play my queen of trumps: the opinion of the experts. The Astronomer Royal, who ought to know, tells me that the earth is round. The Oval Earth man covers the queen with his king. Have I tested the Astronomer Royal's statement, and would I even know a way of testing it? Here I bring out my ace. Yes, I do know one test. The astronomers can foretell eclipses, and this suggests that their opinions about the solar system are pretty sound. I am, to my delight, justified in accepting their say-so about the shape of the earth.
If the Oval Earth man answers — what I believe is true — that the ancient Egyptians, who thought the sun goes round the earth, could also predict eclipses, then bang goes my ace. I have only one card left: navigation. People can sail ship round the world, and reach the places they aim at, by calculations which assume that the earth is spherical. I believe that finishes the Oval Earth man, though even then he may possibly have some kind of counter.
It will be seen that my reasons for thinking that the earth is round are rather precarious ones. Yet this is an exceptionally elementary piece of information. On most other questions I should have to fall back on the expert much earlier, and would be less able to test his pronouncements. And much the greater part of our knowledge is at this level. It does not rest on reasoning or on experiment, but on authority. And how can it be otherwise, when the range of knowledge is so vast that the expert himself is an ignoramus as soon as he strays away from his own specialty? Most people, if asked to prove that the earth is round, would not even bother to produce the rather weak arguments I have outlined above. They would start off by saying that "everyone knows" the earth to be round, and if pressed further, would become angry. In a way Shaw is right. This is a credulous age, and the burden of knowledge which we now have to carry is partly responsible.

New Words
preface
n. an introduction to a book or speech 前言,序

gullible
a. easily deceived or cheated esp. into a false belief; credulous 易受骗的;轻信的

superstitious
a. full of superstition; believing in superstitions 迷信的

credulity
n. a tendency to believe to readily 轻信

cite
vt. mention as an example; quote (a passage, book, etc.) 举出;引出

widespread
a. found or distributed over a large area 分布广的;普遍的

advance
vt. put or bring forward; offer 提出

appeal
vi. please, attract or interest 投合所好;有感染力;有吸引力

mentality
n. way of thinking, outlook; mental power or capacity 心理,思想;脑力

exaggerate
vt. think, speak or write of as greater than is really so; overstate 夸张;夸大

sake
n. end, purpose 缘故

geographer
n. a specialist in geography

ocular
a. of, for, by the eyes; based on what has been seen 眼睛的;凭视觉的

theoretical
a. of or based on theory

citizen
n. 公民;市民

refute
vt. prove (a statement) to be untrue; prove (a person) to be mistaken 驳斥

mast
n. a long upright pole of wood or metal for carrying flags or sails on a ship 桅杆

funnel
n. a metal chimney for letting out smoke from a steam engine or steamship (蒸汽机,轮船等的)烟囱

invisible
a. that can not be seen

horizon
n. the line where the sky seems to meet the earth or sea 地平线

phenomenon (pl. phenomena)
n. 现象

curve
vt. bend so as to form a line that has no straight part 使成曲线
n. a continuously bending line without angles 曲线

follow
vi. result or occur as a consequence, effect, or inference 结果产生;得出

spherical
a. shaped like a ball 球形的

oval
n.& a. (anything which is) egg-shaped 卵形的(东西), 椭圆的(东西)

card
n. 纸牌

analogy
n. comparison of things that have a certain likeness; similarity 类比; 相似

promptly
ad. quickly and willingly 敏捷地;迅速地

prompt a.

body
n. =celestial body 天体

disc
n. 圆盘

cast
vt. throw or drop; cause (light or shadow) to appear (on) 扔,投; 投射

eclipse
n. the total or partial hiding of one celestial body by another (天文学)食

booklet
n. a small book, usu. with a paper cover 小册子

exchange
vt. give and receive (one thing in return for another) 交换

trump
n. 王牌

royal
a. for, belonging to, or connected with a king or queen 皇家的; 王室的

statement
n. expression in words; a written or spoken declaration, esp. of a formal kind 陈述;声明

ace
n. (纸牌中的)"A"牌,爱司

foretell
vt. tell beforehand; predict 预言

solar
a. of the sun

the solar system
the sun and the planets which revolve round it

justify
vt. give a good reason for; show to be just, right or reasonable 证明……是正当的；为…辩护

say-so
n. an authoritative pronouncement; one's unsupported assertion 权威性声明；无证据的断言

Egyptian
n.,a. (native) of Egypt 埃及人；埃及的

predict
vt. announce or tell beforehand; forecast 预言

bang
ad. with a sudden loud noise; with a sudden impact 砰地

navigation
n. the act or process of navigating 航海

calculation
n. the act of adding, subtracting, multiplying, or dividing to find a result 计算

calculate vt.
calculator n. 计算器

counter
n. sth. of value in bargaining; a return attack, such as a blow in boxing 讨价还价的本钱；回击，反击

precarious
a. insecure; depending upon mere assumption 不安全的；根据不足的，靠不住的

exceptionally
ad. unusually

authority
n. power to influence; power to give orders and make others obey 权威；权力

ignoramus
n. an ignorant person 无知的人

stray
vi. wander away; (of thoughts or conversation) move away from the subject 走离；离题

specialty
n. a special field of work or study 专业

outline
vt. indicate the main ideas or facts of
n. a systematic listing of the important points of a subject 提纲

press
vt. demand or ask for continuously 催促，逼迫

credulous
a. tending to believe sth. on little evidence, arising from credulity 轻信的

burden
n. sth. difficult to bear; load 重负；负荷

Phrases & Expressions
follow up
pursue or investigate closely; take further action after (sth.) 深入研究或调查；采取进一步行动

for the sake of
for the good or advantage of; for the purpose of 为了…的利益；为了

throw/shed light on
make clear; explain 使明白，使明朗；解释

and so forth
and so on

as for
with regard to, concerning 至于

may well (not)
be very likely (not) to 完全（不）可能

bring out
show; offer to the public 拿出；使显出；推出（新产品等）

aim at
have as one's target, objective, etc.

fall back on
turn to for support 求助于

rest on
depend on, rely on

stray away from
wander from; move from 偏离

start off
begin; depart

in a way
to a certain extent; a little; somewhat 在某种程度上

Proper Names
Saint Joan
圣女贞德

Bernard Shaw
萧伯纳