SOURCES OF ERROR①IN SCIENTIFIC INVESTIGATION
In Unit 3 we examined briefly the sequence of procedures which make up the so-called scientific method. We are now going to consider a few of the many ways in which a scientist may fall into error③while following④these procedures.
In formulating hypotheses, for example, a common error is the uncritical acceptance of apparently common-sense, but untested, assumptions⑤. Thus in the field of psychology it was for many years automatically assumed that the main cause of forgetfulness is the interval of time clapsing⑥between successive exposures to a learning stimulus. Experimentation, however, was subsequently under- taken, and several other factors, such a6 motivation and the strength or effectiveness of the stimulus, turned out to have an even more important bearing on the problem. A somewhat similar error arises from neglect of multiple causes. Thus two events⑦may be found to be associated, e. g. when the incidence of a disease in a smoky industrial sector of a city is significantly higher than in the smoke-free zones. A research worker might infer that the existence of the disease is due to the smokiness of the area when⑧in fact it might equally well⑨be found in other reasons, such as the under-nourishment of the inhabitants or over-crowding.
Both in collecting the original evidence and in earring out subsequent experiments, a frequent cause of error is the fact that observations are not continued for a long enough time. This may lead not only to a failure to discover positive items (e. g. Le Monnier's failure to recognize that Uranus was a new planet, not a fixed star, etc.), but may also result in important negative aspects of the investigation remaining undiscovered⑩. In applied science, this latter error may have disastrous consequences, as?in the case of the thalidomide drugs?, cancer-inducing industrial chemicals, etc.
Another well-known error in experimentation, is lack of adequate controls (see Unit 3, 11. 39-43). Thus a few years ago it was widely believed that a certain vaccine could prevent the common, cold, since in the experiments the vaccinated subjects reported a decrease in the incidence of colds compared with the previous year. Yet later, more?strictly controlled experiments failed to support this conclusion, which could have been due to a misinterpretation, of chance results?. This error is often caused by a failure to test a sufficient number of subjects (inadequate sampling), a disadvantage?which affects medical and psychological research in particular.
Errors in measurement, particularly where com- plicated instruments are used, are common: they may arise through?lack of skill in the operator or may be introduced through defects in the apparatus itself. Furthermore, it should be borne in mind that apparently minor changes in laboratory conditions, such as variations in the electric current, or failure to maintain atmospheric conditions constant?，may disturb the accuracy of various items of equipment and hence have an adverse influence on the experiment or series of experiments as a whole. In addition, such errors tend to be cumulative.
Finally, emotion?in the observer can be one of the most dangerous sources of error. This may cause the researcher to over-stress?or attach too much importance to irrelevant details because of their usefulness?in. supporting a theory?to which he is personally in clined. Conversely, evidence disproving the view held?may be ignored for similar reasons. Even routine matters?such as the recording of data may be subject to?emotional interference，and should be carefully checked.
To sum up (summarize)?，the multiple possibilities of error are present at every stage of a scientific investigation, and constant vigilance (care) and the greatest foresight must be exercised in order to minimize or eliminate them .Additional errors are，of course, connected with faulty reasoning; but so?widespread and serious are the consequences that may arise from this source that they deserve separate treatment?in the following unit.
译文科研中发生差错的根源
我们在第三讲里已简略地探讨了组成所谓科研方法的一套程序。科学家在按照这套程序进行科研时，还有可能在许多方面出错，现在我们来谈谈其中若干方面。
例如，在提出一项假设时，常见的一种错误是，不加鉴别地采用未经科学验证的论点，尽管这种论点是人所共知的常识。如在心理学中，多年来人们曾想当然地认为，遗忘主要是由于从记入到回忆这两次记忆活动之间的时间间隔所造成，但后来经过实验，结果表明，原来另外还有一些因素，如识记的动机、识记的强度或效率，倒是与遗忘有更大的关系。忽视原因的多种性，是与此相类似的又一种错误，而且这两种错误常常交织在一起。例如，城市中某一种疾病的发病率，在有烟的工业区显然要比无烟地区高得多，于是研究人员可能推断，这种疾病的发生，是由该地区的烟雾所造成。可是实际上，市民营养不良或居住过密等其它原因，也同样可以是致病因素。
无论在收集科研原始数据或在随后所进行的实验时，产生错误的一个常见原因，就是缺乏足够充分的时间进行观察。这样，不仅可能导致不能发现研究项目的某些正面特性（如Le Monnier氏当时未能发现天王星并非恒星，而是一颗新的行星），而且可能对一些很重要的反面特性也不能发现。这后一种错误，在应用科学中会造成极其严重的后果，例如对镇静解痛药物的研究和对具有致癌作用的化工药品的研究，就是例子*。
大家知道，在实验中常发生的另一种错误，就是缺少足够的对照组（参阅第三讲）。比如，几年前人们普遍相信，有一种疫苗能预防普通感冒，因为据接受疫苗试验的人报告说，感冒发病率比上一年有所降低。然而，后来进行了次数更多的严格对照试验/否定了上述结论。之所以得出这种错误结论，是由于将偶然性的结果误以为真。这种错误，往往是由于受试人次太少（取样不足）所造成，其危害所及，对医学研究和心理学研究尤甚。
测量方?的差错，特别是在使用复杂仪器时，也屡见不鲜。其所以发生这种差错，可能是由于操作者技术不熟续，也可能是仪器本身有缺陷。此外，还需要记住，实验室的各种条件，即使发生了看来是很细微的改变（如电流的变化），或者不能使大气诸因素保持恒定，都可能影响仪器设备各部件的精确性，从而对实验乃至整个一系列实验产生不良影响。况且，测量方面的误差，是会逐次累积增加的。
最后，研究人员的主观倾向性可能成为发生错误的最危险的根源之一。带着主观倾向性，研究人员就会过分强调或重视那些迎合他个人观点、但实属无关紧要的枝节问题。反之亦然，对于征明他所持观点是错误的论据，却可能因此遭到漠视，甚至像记录各种数据的实验常规工作，也可能受到主观因素的干扰而出错。所以，务必仔细核对。
综上所述，在科研的每一阶段，都存在着发生错误的种种可能，因此，务必始终保持谨慎态度，并有充分的预见性，以使差错减少到最低限度或完全消除。当然，另外还有一类错误，是由于不正确的思维所造成，由此产生的错误，后果严重，影响甚大，所以值得在下一讲专门加以讨论。
注释
1. error（不可数名词）出错，发生错误；带冠词时通常为可数名词，an error—个错误。
2. way有“方法，途径”等义，但此处不宜译成“发生错误的许多途径”，因为错误是不希望有的，用“途径”两字不妥，可译作“情况或方面”。
3. fall into error出错。
4. while following…现在分词短语作状语，也可看作中间省略了he is的状语从句。
5. common sence a.常识性的（common sence常识），修饰assumptions（此处作“观点、论点”讲）；untested也修饰assumptions，其前有but表示意思转折并强调，故前后用逗号分开。本句也可以顺原文词序译出，如：不加鉴别堆采用显然是常识性的、但却是未经科学验证的论点。译文中修饰语太长，系拘泥于原文结构之故，我们不妨让两个定语各自成句，并将强调部分提前，这就合乎汉语句子要短这个特点。
6. elapsing between…分词短语作定语说明time，learning此处不作“学习”讲，learning stimulus记忆刺激物（指需要记忆的事物）；exposures to（两次）暴露于或接触；successtive连续的。本句直译费解，采用意译法。
7. two events两件事或两种情况，但并非指下文所述烟雾和发病两事，而指上文讲到的两种相似的错误，烟雾和发病这个例子，正是用来说明上述两种类似的错误是常常交织在一起的。
8. when此处意为although。
9. may（might）well+动词原形很可能…例如：It may well rain before tonight。
10. important negative aspects of the investigation remaining undis covered这是带逻辑主语的动名词短语，作result in的宾语。导致（逻辑主语部分）仍未被发现。negative aspects反面特性，不宜译为“否定的…”。诚如文中所述，既要研究药物的正面特性（即治疗作用），也要研究其反面特性（即副作用），从研究角度讲，正反两方面的作用一样重要。
11. as in the case of...像在…情况下那样，像…就是例子。
12.一种解痛、镇静药物，其副作用可使胎儿畸形。
13. more并非说明strictly-controlled，故不能译成“更为严格的对照试验”，它说明experiments行更多次的试验。如仔细领会上下文意思（受试人次不足），这种误译是可以避免的。
14.译为“对偶然性结果的误解”读来仍嫌费解。不妨将“误解”加以引申：对偶然性结果误以为真。
15. a disadvantage说明a failure to test…是同位结构。
16. through=because of。
17. constant a.是atmospheric conditions的补足语。
18. emotion不能译作“情绪”。情绪通常指一个人心情的好坏，怎么情绪可能是产生错误的最危险的根源之一呢？原来emotion的含义包括love，hate，joy，fear等种种感情，通观整段原文，emotion实指根据个人好恶所持的态度，或引申为“个人的主观倾向性”；句中observer与researcher系同一概念，可统一译成“研究人员。”
19. to over-stress和（to）attach too much importance to同义，有时译出其一即可。
20. their usefulness=the usefulness of irrelevant details。
21. theory不作“理论”讲，指一种见解或观点。
22. hold的过去分词作后置定语修饰the view，意为：（该研究人员）所持的观点。
23.指一种职业的常规性工作，如护士给病人测体温、数脉搏等日常必做的工作。
24. be subject（a. ）to…易遭受到…。
25.总之，总而言之（动词不定式做插入语）。
26.这是由so…that…引出结果状语从句的主从复合句，第一个that引出定语从句说明主语the consequences，句中主谓语倒装是为了强调谓语并因主语部分太长之故。
27.直译为：值得分别加以论述。
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*有的镇静解痛药虽有治疗作用（即其正面特性），但有严重副作用（反面特性），妇女服用会使胎儿畸形。