错误的类型
观点会被四个明显的错误类型中的一个带入误区。下面的分类增加了案例作为澄清说明。
1.由于人的本性，错误或者错误的倾向在所有人中是普遍存在的（例如，选择性理解的趋势或匆忙做出判断或将复杂问题简单化）
2.和个人思维习惯或个人态度、信仰或理论相联系的错误或错误倾向（例如，怀有偏见地考虑种族或者宗教中的最坏成员的思维习惯）
3.来自于人类交流和语言限制的错误（例如，不适当地表达一个想法或感觉，引导他人形成错误的印象）
4.在一个时代普遍的错误（例如，在我们祖父年代毫不质疑的接受权威的倾向，或者我们只认可自己却并不认可权威）
当然，有些人比其他人更容易犯错误。英国哲学家约翰洛克（John Locke）观察到他们有三种类别：
几乎不思考的人，他们跟随着他们周边的人思考和行动——父母、邻居、牧师、或任何他们仰慕和尊敬的人。这些人要躲避伴随着自己思考的困难。
决定让情绪而不是理性掌控人生的人。这些人只会被符合他们偏见的理由影响。
真诚地思考，但是缺乏合理的，全面的识别力，并且看不到问题的全部角度。他们倾向于和一种人谈话，读一种书，因此只被一种观点所包围。
对于洛克（Locke’）的清单，我们应该再加上一种：那些从来不愿意对已经形成的观念重新检查的人。这些人通常是最容易犯错的人，因为当新的证据出现时，他们失去了纠正错误的机会。
信息充分的观点和信息不充分的观点
如果专家和我们其他人一样会犯错，为什么他们的意见比那些不是专家的有更高的价值？从我们考虑过的例子来看，我们可能得出结论，咨询专家是浪费时间。让我们看一些情况，分析这个结论是否合理。
吸食大麻有什么影响？我们可以问吸食者的意见或者对一大群吸食者做问卷调查。但是，从经受过训练的观察者，科学研究者那获得意见是更加谨慎的，因为他们进行了大麻吸食影响的研究。（至少有一个这样的团队，一队军医，已经发现重度使用大麻会引起严重的肺部伤害。而且，如果吸食者是精神分裂症的易发人群，大麻会导致持续长时间的精神紊乱）
可能在宇宙的边缘有一个巨大的类星体，距离我们100亿光年。（要用英里来计算距离的话，用时间乘以光速：每秒186,000英里；每天的时间，86,400秒乘以一年的天数，365；最后，再乘以10,000,000,000。）被天文学家观察到的一点点光线在这些时间中穿越了空间刚刚到达我们这里。这个类星体可能在千百万年前就不存在了。是不是？在我们知道以前已经经过了无数的时间。如果我们想知道这个类星体或者关于类星体一般的信息，我们可以在街角拦下一个人问他，然后这个人可以自由发表意见。但是，去询问天文学家会更明智。
鲸鱼会相互交流吗？如果可以，他们可以传递信息多远距离？我们的汽车修理工对此有他的意见吗？或许。还有我们的杂货店商人、牙医和银行家。但是不管这些人有多聪明，他们关于鲸鱼的观点的信息是不充分的。那些已经对鲸鱼做了一些研究的人的意见才是有价值的。（他们可以告诉我们，驼背鲸可以发出不同的声音。除了咔哒声，他们发出嘎吱声和砰砰声和尖叫声。他们被发现可以一次发出这样的声音数分钟，强度在100到110分贝，在25,000英里以外可以被听到。）
可以在每一个知识领域中找到同样的例子——从考古收集到伦理学，从艺术到犯罪学。他们都支持同样的观点：在形成自己的想法前，审查见多识广人的意见，我们可以拓宽视野，看到我们可能自己看不到的细节，考虑我们无法察觉的事实，减少我们犯错的机会。（寻找百分百的正确答案是愚蠢的——它们不存在）。没有人无所不知；没有人有足够的时间学习它们。向那些在自己知识领域中花了足够注意力的人咨询问题，既不是依赖，也不是不负责，而是高效率和明智。
要被认为信息充分，一个观点必须建立在大量材料基础上，而不是我们对它的熟悉程度或者持有时间的长度，或者我们假定的权力去思考任何我们希望的东西。它必须是基于对证据的仔细思考。当我们用正式的口头或书面正式表达观点时，我们应该用充足的证据支持它。比如作者雷马歇尔和马克塔克（Ray Marshall and Marc Tucker,）宣称，在美国教育一直没有成为受尊敬的职业的原因是有传统上绝大多数学校老师都是女性。为了支持这个观点，他们追踪了相关的历史发展，引用了行政指令和思想陈述，展示了雇佣的情况（从1870年妇女占59%到1920年妇女占86%），详细说明课程的重大转变，对比男性和女性的工资统计数据，并证明女性在协商职业水平工资和工作条件方面相对无能为力。
正如这个例子所说明的，在最负责任的意见表达中，意见陈述只占一两句话，而支持性细节则填满很多段落、页面甚至整个章节。在你撰写分析报告时请记住这一点。
Kinds of Errors
Opinion can be corrupted by any one of four broad kinds of errors.* These classifications, with examples added for clarification, are the following:
- Errors or tendencies to error common among all people by virtue of their being human (for example, the tendency to perceive selectively or rush to judgment or oversimplify complex realities)
- Errors or tendencies to error associated with one’s individual habits of mind or personal attitudes, beliefs, or theories (for example, the habit of thinking the worst of members of a race or religion against which one harbors prejudice)
- Errors that come from human communication and the limitations of language (for example, the practice of expressing a thought or feeling inadequately and leading others to form a mistaken impression)
- Errors in the general fashion of an age (for example, the tendency in our grandparents’ day to accept authority unquestioningly or the tendency in ours to recognize no authority but oneself)
Some people, of course, are more prone to errors than others. English
philosopher John Locke observed that these people fall into three groups:
Those who seldom reason at all, but think and act as those around them do—parents, neighbors, the clergy, or anyone else they admire and respect. Such people want to avoid the difficulty that accompanies thinking for themselves.
Those who are determined to let passion rather than reason govern their lives. Those people are influenced only by reasoning that supports their prejudices.
Those who sincerely follow reason, but lack sound, overall good sense, and so do not look at all sides of an issue. They tend to talk with one type of person, read one type of book, and so are exposed to only one viewpoint.13
To Locke’s list we should add one more type: those who never bother to reexamine an opinion once it has been formed. These people are often the most error prone of all, for they forfeit all opportunity to correct mistaken opinions when new evidence arises.
Informed Versus Uninformed Opinion
If experts can, like the rest of us, be wrong, why are their opinions more highly valued than those of nonexpertsIn light of the examples we have considered, we might conclude that it is a waste of time to consult the experts. Let’s look at some situations and see if this conclusion is reasonable.
What are the effects of hashish on those who smoke itWe could ask
the opinion of a smoker or take a poll of a large number of smokers. But it would be more prudent to obtain the opinion of one or more trained observers, research scientists who have conducted studies of the effects of hashish smoking. (At least one such group, a team of army doctors, has found that heavy use of hashish leads to severe lung damage. Also, if the smoker is predisposed to schizophrenia, hashish can cause long-lasting episodes of that disorder.14)
Agiant quasar is positioned on what may be the edge of our universe,
10 billion light-years away from us.15 (To calculate the distance in miles, just multiply the speed of light, 186,000 miles per second, by the number of seconds in a day, 86,400; next multiply that answer by the number of days in a year, 365; finally, multiply that answer by 10,000,000,000.) The pinpoint of light viewed by astronomers has been streaking through space for all those years and has just reached us. The quasar may very well have ceased to exist millions and millions of years ago. Did itIt may take millions and millions of years before we can know. If we wanted to find out more about this quasar or about quasars in general, we could stop someone on a street corner and ask about it, and that person would be free to offer an opinion. But it would be more sensible to ask an astronomer.
Can whales communicate with one anotherIf so, how far can they transmit messagesWould our auto mechanic have an opinion on this matterPerhaps. And so might our grocer, dentist, and banker. But no matter how intelligent these people are, chances are their opinions about whales are not very well informed. The people whose opinions would be valuable would be those who have done some research with whales. (They would tell us that the humpback whales can make a variety of sounds. In addition to clicking noises, they make creaking and banging and squeaking noises. They’ve been found to make these sounds for as long as several minutes at a time, at an intensity of 100 to 110 decibels, and audible for a distance of 25,000 miles.16)
Similar examples could be cited from every field of knowledge—from antique collecting to ethics, from art to criminology. All would support the same view: that by examining the opinions of informed people before making up our minds, we broaden our perspective, see details we might not see by ourselves, consider facts we would otherwise be unaware of, and lessen our chances of error. (It is foolish to look for guarantees of correctness— there are none.) No one can know everything about everything; there is simply not enough time to learn. Consulting those who have given their special attention to the field of knowledge in question is therefore a mark not of dependence or irresponsibility but of efficiency and good sense.
To be considered informed, an opinion must be based on something
more substantial than its familiarity to us or the length of time we have held it or our presumed right to think whatever we wish. It must be based on careful consideration of the evidence. And when we express an opinion in formal speaking or writing, we should support it adequately. Authors Ray Marshall and Marc Tucker, for example, assert that the reason teaching in the United States has not been a highly respected profession is that most schoolteachers traditionally have been women. To support this contention, they trace the relevant historical development, citing administrative directives and statements of philosophy, presenting hiring patterns (from 59 percent women in 1870 to 86 percent in 1920), detailing significant shifts in curricula, contrasting male and female salary statistics, and demonstrating the relative powerlessness of women to negotiate professional-level salaries and working conditions.17
As this example illustrates, in most responsible expressions of opinion, the statement of opinion takes up only a sentence or two, while the supporting details fill paragraphs, pages, and even entire chapters. Keep this in mind when writing your analytic papers.