认知的障碍
在我们讨论如何最好的获得知识前，让我们探讨下两个损害知识的习惯：假设和猜测。假设就是想当然地接受某事——也就是，随意接受未被证实的或者很明显有争议的事情作为真理。因为假设通常是无意识行为，我们经常不会注意到我们的假设和它们对我们的影响。没有识别假设的主要负面影响是，它们会遏制追求知识的好奇心。
比如，很多人从来没有思考过鱼的日常生活。他们可能会偶尔停留在购物中心的宠物店前，盯着水箱里的热带鱼。但是他们从来不会对鱼的群体中社交角色和关系表现出好奇，因为他们假设鱼没有这些角色和关系。但是，用水下社会学家（C. Lavett Smith）的话讲，事实是，“有着类似理发师、警察、和农夫角色的鱼。有些一直在游动，有些静止不动。有些在白天工作，有些在晚上工作”。
猜测是基于预感给出判断，或者在没有任何信心保证正确的情况下选择一个答案。这是一种常见的日常活动。对于那些没有为考试而学习的学生来说，这是最后的生存技巧。对于猜测的案例，我们还是举一个愉快的话题——喝啤酒。不久前，加州一所大学的行为科学教授在他的学生中进行了一次啤酒味道测试。测试题目是他们是否真的能分辨出好啤酒和坏啤酒，或者从其他的啤酒中辨别出自己最喜爱的。许多学生可能会认为他们能猜到，并且测试中的一些参与者确实也认为他们能分辨出来。然而，测试表明，当样品没有贴标签时，没有一个学生能识别出一个品牌。
因为假设遏制了好奇心，猜测放弃了证据的重要性，因此，两者都不大可能带来知识。最可靠的方法是小心地断言你知道什么。就你确认的程度上保守一些——任何时候当你不确定时，就说可能性或者概率。说，“我想”或者“我认为”，不要说“我知道”。最重要的是，对你和其他人坦诚你的无知。承认你不知道会显示出感觉良好、克制和学术真诚。这不是脆弱而是强大。对无知的承认是通往知识的关键的第一步。
这是否意味着你应该说空洞无物的话，对任何事情都说可能和或许？这是否意味着要成为批判性思维者，你必须放弃确信？对这两个问题的答案是大大的“不”！这仅仅意味着你应该重视坚定、大胆的陈述，这样，在证据允许的情况下，你拥有它们。同样地，只有当你有足够的知识时，你应该高度重视信念并接受它们，并且在学术诚实需要的时候，你会对它们进行修改。
原文
Obstacles to Knowledge
Before we discuss how knowledge is best sought, let’s consider two habits that impede knowledge: assuming and guessing. Assuming is taking something for granted—that is, arbitrarily accepting as true something that has not been proved or that may reasonably be disputed. Because assuming is generally an unconscious activity, we are often unaware of our assumptions and their influence on us.* The main negative effect of unrecognized assumptions is that they stifle the curiosity that leads to knowledge.
Many people, for example, never speculate about the daily life of fish. They may occasionally stop at the pet store in the mall and stare at the tank of tropical fish. But they may never display curiosity about the social roles and relationships of fish communities because they assume fish have no such roles or relationships. Yet the fact is, in the words of underwater sociologist C. Lavett Smith, “There are fish equivalents of barbers, policemen, and farmers. Some are always on the move and others are sedentary. Some work at night and some by day.”22
Guessing is offering a judgment on a hunch or taking a chance on an answer without any confidence that it is correct. It’s a common, everyday activity. For students who don’t study for exams, it’s a last-ditch survival technique. For an example of guessing, though, let’s take a more pleasant subject—drinking beer. Some time ago a professor of behavioral science at a California college conducted a beer taste test among his students. The issue was whether they could really tell a good beer from a bad one or their favorite from others. Many students likely would guess they could, and a number of participants in the test actually guessed they could tell. However, the test showed that when the samples were not labeled, not one student could identify a single brand.23
Because assuming stifles curiosity and guessing denies the importance of evidence, neither is likely to lead to knowledge. The most reliable approach is to be cautious in asserting that you know something. Be conservative in your level of assertion—whenever you are less than certain, speak about possibilities and probabilities. Say, “I think” or “It seems to me” rather than “I know.” Most important, be honest with yourself and others about your ignorance. To admit you don’t know something shows good sense, restraint, and intellectual honesty. These are not weaknesses but strengths. The admission of ignorance is the essential first step toward knowledge.
Does this mean you should be wishy-washy and hedge everything you say with maybes and perhapses? Does it mean that to be a critical thinker you must forsake convictions? The answer to both questions is an emphatic no! It means only that you should value firm, bold statements so much that you reserve them for occasions when the evidence permits. Similarly, you should value convictions so highly that you embrace them only when you have sufficient knowledge to do so and that you modify them whenever intellectual honesty requires.
