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 易受騙的;輕信的

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

credulity
n. a tendency to believe to readily 輕信

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

widespread
a. found or distributed over a large area 分布廣的;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;腦力

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

sake
n. end, purpose 緣故

geographer
n. a specialist in geography

ocular
a. of, for, by the eyes; based on what has been seen 眼睛的;憑視覺的

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 駁斥

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

funnel
n. a metal chimney for letting out smoke from a steam engine or steamship (蒸汽機,輪船等的)煙囪

invisible
a. that can not be seen

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

phenomenon (pl. phenomena)
n. 現象

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

follow
vi. result or occur as a consequence, effect, or inference 結果產生;得出

spherical
a. shaped like a ball 球形的

oval
n.& a. (anything which is) egg-shaped 卵形的(東西), 橢圓的(東西)

card
n. 紙牌

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

promptly
ad. quickly and willingly 敏捷地;迅速地

prompt a.

body
n. =celestial body 天體

disc
n. 圓盤

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 (天文學)食

booklet
n. a small book, usu. with a paper cover 小冊子

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

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 陳述;聲明

ace
n. (紙牌中的)"A"牌,愛司

foretell
vt. tell beforehand; predict 預言

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 證明……是正當的；為…辯護

say-so
n. an authoritative pronouncement; one's unsupported assertion 權威性聲明；無證據的斷言

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

predict
vt. announce or tell beforehand; forecast 預言

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 計算

calculate vt.
calculator n. 計算器

counter
n. sth. of value in bargaining; a return attack, such as a blow in boxing 討價還價的本錢；回擊，反擊

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

exceptionally
ad. unusually

authority
n. power to influence; power to give orders and make others obey 權威；權力

ignoramus
n. an ignorant person 無知的人

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

specialty
n. a special field of work or study 專業

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

press
vt. demand or ask for continuously 催促，逼迫

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

burden
n. sth. difficult to bear; load 重負；負荷

Phrases & Expressions
follow up
pursue or investigate closely; take further action after (sth.) 深入研究或調查；采取進一步行動

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

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

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；使顯出；推出（新產品等）

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 偏離

start off
begin; depart

in a way
to a certain extent; a little; somewhat 在某種程度上

Proper Names
Saint Joan
圣女貞德

Bernard Shaw
蕭伯納