第一篇:GMAT逻辑“ 黑体字” 题型的总结
Bold Face Practice 1.Modern navigation systems, which are found in most of today’s commercial aircraft, are made with low-power circuitry, which is more susceptible to interference than the vacuum-tube circuitry found in older planes.(Fact)During landing, navigation systems receive radio signals from the airport to guide the plane to the runway.(Principle)
Recently, one plane with low-power circuitry veered off course during landing, its dials dimming, when a passenger turned on a laptop computer.(Evidence)Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers.(Conclusion)
2.A double-blind study, in which neither the patient nor the primary researcher knows whether the patient is being given the drug being tested or a placebo, is the most effective procedure for testing the efficacy of a drug.(Principle)But we will not be able to perform such a study on this new drug, since the drug will have various effects on the patients’ bodies, which will make us aware of whether the patients are getting the drug or a placebo.(Anti-Consideration)
3.The interstitial nucleus, a sub-region of the brain’s hypothalamus, is typically smaller for male cats than for female cats.(Fact)A neurobiologist performed autopsies on male cats who died from disease X, a disease affecting no more than 0.5 percent of male cats, and found that these male cats had interstitial nuclei that were as large as those generally found in female cats.(Evidence)
Thus, the size of the interstitial nucleus determines whether or not male cats can contract disease X,(Consideration that can be drawn from the first one)but, the hypothalamus is known not to be causally linked to disease Y, and disease X is a subtype of disease Y.(Fact)4.More and more computer programs that provide solutions to mathematical problems in engineering are being produced, and it is thus increasingly unnecessary for practicing engineers to have a thorough understanding of fundamental mathematical principles.(Conclusion)Consequently, in training engineers who will work in industry, less emphasis should be placed on mathematical principles, so that space in the engineering curriculum will be available for other important subjects.(Conclusion)
5.Gasoline-powered boat engines manufactured in the a North American country prior to 1990 contribute significantly to the pollution found in the world’s oceans.(Fact)
In 1990, however, the government imposed stricter pollution controls on gasoline engines manufactured for boats, and beginning in 1995, the government imposed a program of inspections for pre-1990 boat engines with increasingly rigorous pollution standards.(Fact)
As the older boat engines fail to pass inspection, boat owners are increasingly retiring their old engines in favor of newer, less-polluting boat engines.(The evidence showed in the patten of cause and effect)As a result, the amount of pollution these older boat engines emit into the world’s oceans will steadily decrease over the next ten years.(Conclusion)
6.Plants that exhibit certain leaf diseases tend to measure extremely high in the amount of zinc in their leaf and stem tissue.(Fact or Background)Botanists have discovered that phosphorus of the type typically used in a phosphorus-high fertilizer reacts with the zinc in such a way as to prevent treated plants from exhibiting the leaf diseases, and zinc is the cause and not merely an effect of the leaf diseases.(The second evidence found by the author of passage)Thus, plants can be cured from these leaf diseases by the use of a fertilizer high in phosphorus.(Conclusion)7.To be accepted as a member at the Brown Country Club, one must have a net worth of over ten million dollars and must not have any connections to the entertainment industry.Robert Chase, the publishing magnate, has a net worth of 5 billion dollars and Chase has not financed any Hollywood movies,(The part of evidence in support of this argument)so he must be accepted as a member at the Brown Country Club.(The conclusion that could not be drawn from all evidences that the argument contains)
8.The survival of the publishing industry depends upon the existence of a public who will buy the printed word in the form of newspapers, books and magazines.(Premise)Over the past several years, however, the advance of electronic media, particularly CD-ROMs, online computer services, and the Internet, has made information available to the public electronically without the need for printed materials.(Fact)
As the availability of electronic media increases and as it is more easily accessible, the public has less need for printed materials.(The author’s evidence)So the publishing industry is threatened by the advance of the computer information age.(The author’s conclusion)
9.Something must be done to ease traffic congestion.(Conclusion)In traditional small towns, people used to work and shop in the same town in which they lived(Evidence);
but now that stores and workplaces are located far away from residential areas, people cannot avoid traveling long distances each day.(Evidence)Traffic congestion is so heavy on all roads that, even on major highways where the maximum speed limit is 55 miles per hour, the actual speed averages only 35 miles per hour.(Evidence)
So new businesses should be encouraged to locate closer to where their workers would live.(Author’s method or strategy)
10.(OG-205)Consumer advocate:
it is generally true, at least in this state, that lawyers who advertise a specific service charge less for that service than lawyers who do not advertise.(Concession)It is also true that each time restrictions on the advertising of legal services have been eliminated, the number of lawyers advertising their services has increased and legal costs to consumers have declined in consequence.(Second concession / A pattern of cause and effect that the advocates argues will not hold in the case at issue)However, eliminating the state requirement that legal advertisements must specify fees for specific services would almost certainly increase rather than further reduce consumer’s legal costs.(A certain position advocate hold)Lawyers would no longer have an incentive to lower their fees when they begin advertising and if no longer required to specify fee arrangements, many lawyers who now advertise would increase their fees.(A consideration in support of that prediction)
GWD-1-Q3: A product that represents a clear technological advance over competing products can generally command a high price.Because technological advances tend to be quickly surpassed and companies want to make large profits while they still can, many companies charge the greatest price the market will bear when they have such a product.(a consideration raised to explain the appeal of a certain strategy)
appeal: 呼籲,請求
But large profits on the new product will give competitors a strong incentive to quickly match the new product’s capabilities.(a consideration raised to call into question the wisdom of adopting that strategy)Consequently, the strategy to maximize overall profit from a new product is to charge less than the greatest possible price.(Author’s method or strategy)GWD-1-Q22&8-Q31: City Official:
At City Hospital, uninsured patients tend to have shorter stays and fewer procedures performed than do insured patients, even though insured patients, on average, have slightly less serious medical problems at the time of admission to the hospital than uninsured patients have.Critics of the hospital have concluded that the uninsured patients are more receiving proper medical care.(the position that the city official’s argument opposes)
However, this conclusion is almost certainly false.(the conclusion of the city official’s argument)
Careful investigation has recently shown two things: insured patients have much longer stays in the hospital than necessary, and they tend to have more procedures performed than are medically necessary.(Evidence)
GWD-3-Q2 Hunter:
Hunters alone are blamed for the decline in Greenrock National Forest’s deer population over the past ten years.Yet clearly, black bears have also played an important role in this decline.(the main conclusion of the argument)
In the past ten years, the forest’s protected black bear population has risen sharply, and examination of black bears found dead in the forest during the deer hunting season showed that a number of them had recently fed on deer.(Evidence)
GWD-3-Q16: Economist:
Tropicorp, which constantly seeks profitable investment opportunities, has been buying and clearing sections of tropical forest for cattle ranching, although pastures newly created there become useless for grazing after just a few years.The company has not gone into rubber tapping, even though greater profits can be made from rubber tapping, which leaves the forest intact.(supports the environmentalists’ conclusion)
Thus, some environmentalists conclude that Tropicorp has not acted wholly out of economic self-interest.(states that environmentalists’ conclusion)
However, these environmentalists are probably wrong.The initial investment required for a successful rubber-tapping operation is larger than that needed for a cattle ranch.Furthermore, there is a shortage of workers employable in rubber-tapping operations, and finally, taxes are higher on profits from rubber tapping than on profits from cattle ranching.GWD-5-Q19: Historian:
In the Drindian Empire, censuses were conducted annually to determine the population of each village.Village census records for the last half of the 1600’s are remarkably complete.(provides a context for certain evidence that supports the position that the historian seeks to establish)
This very completeness makes one point stand out;in five different years, villages overwhelmingly reported significant population declines.Tellingly, each of those five years immediately followed an increase in a certain Drindian tax.This tax, which was assessed on villages, was computed by the central government using the annual census figures.Tellingly: 有效地;顯著地
Obviously, whenever the tax went up, villages had an especially powerful economic incentive to minimize the number of people they recorded;and concealing the size of a village’s population from government census takers would have been easy.Therefore, it is reasonable to think that the reported declines did not happen.(that position)
GWD-5-Q20: Scientists typically do their most creative work before the age of forty.It is commonly thought that this happens because aging by itself brings about a loss of creative capacity.(an explanation that the argument challenges)
However, studies show that a disproportionately large number of the scientists who produce highly creative work beyond the age of forty entered their field at an older age than is usual.(a finding on which that challenge is based)
Since by the age of forty the large majority of scientists have been working in their field for at least fifteen years, the studies’ finding strongly suggests that the real reason why scientists over forty rarely produce highly creative work is not that they have simply aged but rather that they generally have spent too long in a given field.天山Q25: Scientists typically do their most creative work before the age of forty.It is commonly thought that this happens because aging by itself brings about a loss of creative capacity.(an explanation that the argument challenges)However, a study has found that almost all scientists who produce highly creative work beyond the age of forty entered their fields late and less than a dozen years before their creative breakthroughs.Since creative breakthroughs by scientists under forty also generally occur within a dozen years of the scientist’s entry into the field, the study’s finding strongly suggests that the real reason why scientists over forty rarely produce highly creative work is not due to age but rather because most have spent too long in their fields.(evidence in support of a competing explanation that the argument defends.)GWD-6-Q16: Historian:
Newton developed mathematical concepts and techniques that are fundamental to modern calculus.Leibniz developed closely analogous concepts and techniques.It has traditionally been thought that these discoveries were independent.Researchers have, however, recently discovered notes of Leibniz’ that discuss one of Newton’s books on mathematics.Several scholars have argued that since the book includes a presentation of Newton’s calculus concepts and techniques, and since the notes were written before Leibniz’ own development of calculus concepts and techniques, it is virtually certain that the traditional view is false.(evidence that has been used to support a conclusion that the historian criticizes)
A more cautious conclusion than this is called for, however.Leibniz’ notes are limited to early sections of Newton’s book, sections that precede the ones in which Newton’s calculus concepts and techniques are presented.(evidence offered in support of the historian’s own position)
GWD-7-Q18&8-Q21: Although the earliest surviving Greek inscriptions written in an alphabet date from the eighth century B.C., a strong case can be made that the Greeks actually adopted alphabetic writing at least two centuries earlier.(the position that the argument seeks to establish)
Significantly, the text of these earliest surviving Greek inscriptions sometimes runs from right to left and sometimes from left to right.(Evidence in support of the position that the argument seeks to establish)Now, the Greeks learned alphabetic writing from the Phoenicians, and in the process they would surely have adopted whatever convention the Phoenicians were then using with respect to the direction of writing.(presents an assumption on which that argument relies.)Originally, Phoenician writing ran in either direction, but by the eighth century B.C.it had been consistently written from right to left for about two centuries.GWD-9-Q30: Criminologist:
Some legislators advocate mandating a sentence of life in prison for anyone who, having twice served sentences for serious crimes, is subsequently convicted 21 of a third serious crime.These legislators argue that such a policy would reduce crime dramatically, since it would take people with a proven tendency to commit crimes off the streets permanently.(a conclusion that the argument as a whole seeks to refute)
What this reasoning overlooks, however, is that people old enough to have served two prison sentences for serious crimes rarely commit more than one subsequent crime.Filling our prisons with such individuals would have exactly the opposite of the desired effect, since it would limit our ability to incarcerate younger criminals, who commit a far greater proportion of serious crimes.(the main conclusion of the argument)
GWD-10-Q17: Editorial: An arrest made by a Midville police officer is provisional until the officer has taken the suspect to the police station and the watch commander has officially approved the arrest.Such approval is denied if the commander judges that the evidence on which the provisional arrest is based is insufficient.A government efficiency expert has found that almost all provisional arrests meet standards for adequacy of evidence that watch commanders enforce.The expert therefore recommends that the watch commander’s approval should no longer be required since the officers’ time spent obtaining approval is largely wasted.(a proposal against which the editorial is directed)This recommendation should be rejected as dangerous, however, since there is no assurance that the watch commanders’ standards will continue to be observed once approval is no longer required.(a judgment reached by the editorial concerning that proposal.)GWD-12-Q33: Several of a certain bank’s top executives have recently been purchasing shares in their own bank.(describes the circumstance the explanation of which is the issue that the argument addresses)
This activity has occasioned some surprise, since it is widely believed that the bank, carrying a large number of bad loans, is on the brink of collapse.Since the executives are well placed to know their bank’s true condition, it might seem that their share purchases show that the danger of collapse is exaggerated.However, the available information about the bank’s condition is from reliable and informed sources, and corporate executives do sometimes buy shares in their own company in a calculated attempt to calm worries about their company’s condition.On balance, therefore, it is likely that the executives of the bank are following this example.(states the main conclusion of the argument.)天山Q3: Business Consultant:
Some corporations shun the use of executive titles because they fear that the use of titles indicating position in the corporation tends to inhibit communication up and down the corporate hierarchy.(consideration that has led to the adoption of a certain strategy)Since an executive who uses a title is treated with more respect by outsiders, however, use of a title can facilitate an executive’s dealings with external businesses.(a reason against adopting that strategy)The obvious compromise is for these executives to use their corporate titles externally but not internally, since even if it is widely known that the corporation’s executives use executive titles outside their organization, this knowledge does not by itself inhibit communication within the corporation.天山Q32: Ecologist:
The Scottish Highlands were once the site of extensive forests, but these forests have mostly disappeared and been replaced by peat bogs.The common view is that the Highlands’ deforestation was caused by human activity, especially agriculture.However, agriculture began in the Highlands less than 2,000 years ago.(evidence that, in light of the evidence provided in the second, serves as grounds for the ecologist’s rejection of a certain position.)Peat bogs, which consist of compressed decayed vegetable matter, build up by only about one foot per 1,000 years and, throughout the Highlands, remains of trees in peat bogs are almost all at depths great than four feet.(the evidence)Since climate changes that occurred between 7,000 and 4,000 years ago favored the development of peat bogs rather than the survival of forests, the deforestation was more likely the result of natural processes than of human activity.8月JJ真题
A prominent investor who holds a large stake in the Burton Tool company has recently claimed that the company is mismanaged, citing as evidence the company’s failure to slow production in response to a recent rise in its inventory of finished products.(the position that the argument as a whole opposes)
It is doubtful whether an investor’s sniping at management can ever be anything other than counterproductive, but in this case it is clearly not justified.(the conclusion of the argument as a whole)It is true that an increased inventory of finished products often indicates that production is outstripping demand, but in Burton’s case it indicates no such thing.Rather, the increase in inventory is entirely attributable to products that have already been assigned to orders received from customers.
第二篇:GMAT高分TIPS-逻辑题型标志词总结
内容提要:在面对GMAT逻辑题目的时候,第一步就是看准问题,明确题目类型,从而运用不同的技巧解题。下面我们就对各种题型的关键词做一个总结,希望可以帮助你在考场上从容面对各种问题。
一.归纳题
标志词:conclusion;inferred;implied;supported;if above true, then it is also true。(注:support不仅仅用于归纳法。举例来说,归纳法的表达应为:Which of the following are supported by the argument above?如果换个说法就可以变成加强题型的表述:Which of the following support the argument above?所以在解题的时候要格外小心。)
二.演绎题
1.第一种文章:前提推结论型
A.假设题:
标志词:assume;assumption;presuppose(特指对于前提的假设);additional premise;not true unless;depend on;rely on.B.加强题:
标志词:support(注意和归纳题目的区分);strengthen, conclusion can be drawn if it were true that.C.削弱题:
标志词:weaken;cast doubt;argue against;damage;counter;challenge;flaw;refute;jeopardize;criticism;undermine;drawback;reasoning error;weakness.(其中flaw,criticism,reasoning error和weakness属于名词性的削弱)。
D.评价题:
标志词:evaluate,appraisal(根据加强题做)
2.第二种文章:因果结构
文章内部标志词:A is due to B;A is attribute to B;A is result of B;blame B on/for A;B is responsible for
A;credit A to B.问题中的标志词:explanation;interpretation;hypothesis。
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3.第三种文章:“变态结构”(表面上仍然是前提推出结论的结构,实质为因果结构,即结论是前提的解释)。此类文章没有与众不同的标志词,需要考生在实战时分析判断。
从题型上看,第一类文章的线索显然多于后两类,也就是说解题上较为方便,幸运的是第一类题目一般占去了考题的绝大部分,所以说还是有技巧可寻的。
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第三篇:逻辑总结gmat
逻辑的最高境界是不是那种,看到问题和题干,就知道ETS会出什么答案的感觉?
放几条刚刚总结的规律,抛砖引玉
名词解释
evidence:证据,现象等,一般指A conclusion:判断,推论等,一般指B 元素:指evidence和conclusion中的主语谓语或宾语(很重要!)
一、归纳,conclusion题型
1、有两个及以上的evidence,没有conclusion,但有推理关系,答案就是是conclusion
2、有两个及以上的evidence,且有数字作为evidence的,答案是需要计算一下元素和数字关系的conlusion 3:有evidence和conclusion,但evidence会影响到conclusion的准确性,答案是conlusion不正确 A、上来就说conclusion,但举出来了一条evidence是特例,答案是conlusion会被其他元素影响到
B、上来就说conclusion,然后举出了一条影响conclusion正确的evidence,答案是conlusion被过高或过低估计了
4、有evidence和conclusion,但彼此之间无关联,答案是evidence和conclusion无关系
5、有evidence和conclusion,但彼此矛盾,答案是conclusion不存在
6、有evidence和conclusion,且结构比较完整无疏漏,答案是evidence的复述
7、有evidence和conclusion,且conclusion是两个元素进行比较的结构,答案是conclusion的进行比较的另一种写法
二、演绎题
(一)假设题
1、有evidence和conclusion,推理过程完整,答案是把conclusion的元素和evidence的元素搭桥建立关系
A、情况A,当evidence和conclusion各有一个,并且都有一个共同的元素时,把conclusion独有元素和evidence的独有的元素建立关系。B、情况B,有多个evidence和一个conclusion时,把conclusion和一个evidence共同用的元素和另外一个evidence的独有的元素建立关系。
2、有evidence和conclusion,推理过程不完整,缺乏某一个应该出现的evidence,答案是这个evidence
3、答案中含有not,分为不能被他因削弱和evidence的元素不能没有关系两种
(二)加强题
1、有evidence和conclusion,推理过程完整,答案是把conclusion的元素和evidence的元素搭桥关系
2、有evidence和conclusion,推理过程完整,答案是一个事实说明conclusion成立
3、有evidence和conclusion,推理过程为conclusion解释evidence,本身已经构成充要条件,答案为evidence的逆否命题
(三)weaken题
1、有evidence和conclusion,但evidence存在不完整性或不正确,答案是evidence为啥不完整或不正确
2、有evidence和conclusion,且推理逻辑上正确,答案是其他的evdence在发挥作用
3、有evidence和conclusion,但推理不正确,答案是conclusion的独有元素和evidence的独有元素不具备关系
4、有evidence和conclusion,推理过程为conclusion解释evidence,答案是其他的evdence在发挥作用
(四)评价题
1、有evidence和conclusion,答案是已经存在的evidence的扩大化或缩小化等评价性描述
三、解释题
1、有evidence和conclusion,答案是evidence的补充和完善,基于适当的推理和常识
四、填空题
1、有evidence和conclusion,答案是连接conclusion的元素和evidence的元素
还应该有些类型,我还在陆续总结中,比如说有一些难题的答案,会是常规答案进一步推理,比如必要条件或充分条件。还有一些答案用到了常识推理,比如价格原理等等。都应该是难题了。
第四篇:gmat逻辑解题技巧介绍
gmat逻辑题对于一部分同学们来说是比较难的,那么gmat逻辑题复习的时候大家要注意哪些问题,gmat逻辑题的解题技巧通常都有哪些,下面小编就gmat逻辑复习解题技巧为大家讲解。
我们知道gmat逻辑推理的题目设计目的就是考察一个人能否抓住一个论断的推理主线,评估其他论据对论断所起作用的能力,如果我们对gmat逻辑推理所要考察我们的各项能力进行有针对性的训练,那么突破gmat逻辑推理也并非难事!具体而言,gmat逻辑推理就是要考察我们评价一个论述并形成或评价行动方案的能力,无论如何这都脱离不了正确的解题方法,下面我们一起来看看gmat逻辑推理题解题步骤。gmat逻辑推理解题步骤——读题干:在阅读短文以前先阅读题干,从题干中获得有用的线索,另外还需要考生通过阅读题干能够预测在阅读过程中要寻找什么内容及思考什么内容。
gmat逻辑推理解题步骤——读短文:这一步为逻辑推理解题的核心步骤,当阅读短文的时候,考生需要假定短文中所出现的所有前提都是事实,这里需要向读者强调的一点是逻辑推理题不会考察考生对短文所涉及的专业知识的了解程度,短文中出现的前提是不是事实并非重要,重要的是我们的解题思路是否清晰正确。多数短文通常由前提与结论构成,结论在短文中出现的位置并不总是一致,有时在开头,有时在中间,还有时在结尾。如果你还没有对短文的意思理解透彻,那么这时一个最为理智有效的办法就是先找出结论,之后在试着逐步分析从前提到结论的推理过程。
gmat逻辑推理解题步骤——选答案:完成以上两步骤之后,也可以说你已经完成了一大半的任务,剩下的就是对最佳答案与次优答案进行识别和排除。逻辑推理题中一般不会出现两个或两个以上选项同时实现问题的目的,读者只要选出一个最能实现问题目的的答案就可以。
gmat逻辑推理正确的思维方法是巧取高分的必由之路在解决gmat逻辑推理题的过程中,我们的唯一目的就是去寻求一个使结论成立的可能性增大或减少的答案,而非必须要去寻求一个使结论必然成立的答案。很多考生在解题的过程中总是试图一定让答案至少看起来完美,但是即使是使得结论正确的那个条件找到,我们还是不能保证结论就一定正确。还有一点需要考生特别记住的就是由于GMAC的制题原则就是无需专业背景知识原则,因此只要考生将思维放在题目以内进行思考,而非对段落进行额外的无用扩充,尤其是考生不应在解题的过程应用自己的专业知识进行递进推理。
gmat逻辑推理题的解题技巧有哪些,以上就是小编为各位总结的关于gmat逻辑推理题解题步骤的相关介绍相信大家通过上文对于gmat逻辑推理题解题技巧能够有所了解了吧。
第五篇:MBA逻辑基础知识+题型总结
MBA逻辑基础知识总结
1. 演绎推理:
a)联言推理:p并且q b)选言推理:相容、不相容
c)假言推理:充分、必要
d)多重复合命题推理:假言连锁(充分、必要)、假言易位、反三段论 e)直言命题对当关系:反对、下反对、矛盾、差等 f)直言换位推理:词项的周延、直言命题换位推理 g)三段论: 格和式、规则。h)模态命题的转换 2. 归纳推理:
a)完全归纳属于必然推理 b)不完全归纳属于或然推理
3. 类比推理:
根据两个对象在一系列属性上是相同的,而且知道其中的一个对象还具有另一种属性,由此推出另一个对象也具有这一属性的推理。4. 逻辑基本规律:
a)同一律:A是A
在同一思维过程中,反映同一对象的思想必须是确定的,必须保持自身的统一。b)矛盾律:A不是非A
在同一思维过程中,互相否定的思想不能同时都是真的;或者说,对同一对象不能有相互否定的思想。c)排中律:A或者非A
在同一思维过程中,两个相互矛盾的思想必有一真,不能都假。5. 因果关系:
a)求同法:异中求同
在被研究的现象出现的若干场合中,如果有唯一的情况是这些场合中共有的,那么这个唯一的共同情况就是被研究现象的原因(或结果)。
b)求异法:同中求异
比较被研究的现象出现的场合与被研究的现象不出现的场合,其他的情况完全相同,只有一个情况是不同的,而这唯一的不同的情况表现为,在被研究的现象出现的场合中它出现,在被研究的现象不出现的场合中,它不出现。那么,这个唯一不同的情况就是被研究现象的原因(或结果)。c)共变法:
在被研究现象发生变化的各个场合,如果其中只有一个情况是变化着的,而其他的情况都保持不变,那么这个唯一变化着的情况就是被研究现象的原因。
1. 演绎推理:
a)联言推理:
一般形式:p并且q;
真值:只有p和q都真的情况下,“p并且q”才真。否则,为假。
连接词:并且、和、既......又……、一方面……另一方面……、虽然……但是……、不但……而且……、既是……又是……、尽管……然而……等等。
负命题:“并非(p并且q)”等值于“非p或者非q” 几个重要等值关系:
并非(p并且q)”《=》“非p或者非q”;
并非(p并且q)”《=》“如果p,那么非q;
“非p或者非q”《=》“如果p,那么非q;
b)选言推理:相容、不相容 1)相容选言:
一般形式:p或者q 真值:只要p或者q有一个为真,“p或者q”就为真。
只有p和q都假,“p或者q”才为假。
连接词:或者
负命题:“并非(p或者q)”等值于“非p并且非q”
有效推理形式:否定肯定式
由于它断定了选言支中至少有一个选言支是真的,因此,否定其中一个选 言支,就可以断定其余的选言支中至少有一个是真的。其有效的推理形式为:
p或者q;
p或者q; 非p,非q,所以,q。
所以,p。
注意:相容选言,不能通过可定某一个选言支,而否定其它选言支。
2)不相容选言:
一般形式:要么p, 要么q.真值:只有p或者q一个为真的时候,“要么p, 要么q”为真; 当p和q全真或全假的时候,“要么p, 要么q”为假。
连接词:要么……,要么……。
负命题:不研究
有效推理形式:否定肯定式、肯定否定式
不相容选言命题断定两个选言支中有且只有一个选言支是真的,所以,我 们既可以肯定其中一个选言支,而否定另一个宣言支。也可以否定其中一个选 言支,从而肯定另外一个选言支。其有效的推理形式为:
要么p, 要么q;
要么p, 要么q; 非p,非q,所以,q。
所以,p。要么p,要么q;
要么p,要么q; p,q, 所以,非q。
所以,非p。
c)假言推理:充分、必要
1)充分条件:
一般形式:如果p, 那么q。
几个重要等值关系:
如果p, 那么q。《=》 所有p是q。
如果p, 那么q。《=》 只有q,才p。
如果p, 那么q。《=》 或者非p或者q。
如果p, 那么q。《=》 并非(p并且非q)。
真值:只有p真,q假的时候,“如果p, 那么q”才假。其它情况都为真。连接词:如果……那么……、如果……则……、若……则……、只要……就……、既然……那就……、既然……那么……等等。负命题:“并非(如果p,那么q)”等值于“p并且非q” 有效的推理形式:肯前、否后。如果p,那么q;
p,所以,q。
如果p,那么q; 非q,所以,非p。
2)必要条件:
一般形式:只有p,才q。
几个重要等值关系:
“只有p,才q”《=》“如果非p,那么非q”
“只有p,才q”《=》“如果q,那么p”
“除非p,否则q” 《=》 “只有p,才非q”
真值:只有p假,q真的时候,“只有p,才q”才假。其它情况都真。
连接词:不……不……、只有……才……、除非……否则……等等。
负命题:“并非(只有p,才q)”等值于“非p并且q”。
有效的推理形式:否前、肯后
只有p,才q;
非p,d)多重复合命题推理:假言连锁(充分、必要)、假言易位、反三段论 1)假言连锁(充分、必要):
如果p,那么q;
如果q,那么r; 所以,如果p,那么r。
只有p,才q; 只有q,才r; 所以,只有p,才r。
所以,非q。
只有p,才q; q,所以,p。
2)假言易位:
是指将一个充分条件假言的前件和后件否定后再互易其位置而得出的一 个新的假言命题的形式。如果p,那么q;
所以,如果非q,那么非p。3)反三段论:
如果p并且q,那么r;
非r,并且p; 所以,非q e)直言命题对当关系:反对、下反对、矛盾、差等
1)反对(全肯与全否):不可同真,可以同假。
意味着,一个真可以推出另外一个假;但一个假推不出另外一个真假;
2)下反对(特肯与特否):不可同假,可以同真。
意味着,一个假可以推出另外一个真;但一个真推不出另外一个真假; 3)矛盾(全肯与特否、全否与特肯):不可同真,不可同假;必有一真,必有一假。
意味着,一个真,可以推出另外一个假;一个假可以推出另外一个真; 4)差等(全肯与特肯、全否与特否):
全称真则特称真,特称假则全称假;特称真推不出全称真假,全称假推不 出特称的真假。
f)直言换位推理:词项的周延、直言命题换位推理 1)直言命题的周延原则:
第一,全称命题主项周延,特称命题主项不周延;
第二,否定命题的谓项周延,肯定命题谓项不周延。2)直言命题换位推理:
全肯命题:“所有S都是P”限制性换位为“有些P是S”
全否命题:“所有S都不是P”简单换位为“所有P都不是S”
特肯命题:“有的S是P”简单换位为“有的P是S”
特否命题:不能进行换位
g)三段论: 格和式、规则。
格:即中项在大、小前提中的位置不同,而构成的不同三段论格式;
式:即前提和结论由A、E、I、O命题构成的不同组合。规则:
1)一个三段论有且只能有三个词项; 2)中项在前提中至少周延一次;
3)在前提中不周延的词项,在结论中不得周延; 4)两个前提中有一个是否定的,则结论必须是否定的; 5)两个前提中有一个是特称的,则结论必须是特城的; 6)两个否定的前提,推不出结论; 7)两个特称的前提,推不出结论。
h)模态命题的转换:
第一步,变换量词:“全称”与“特称”互换; 第二步,变换模态词:“必然”与“不可能”互换,“可能”与“不必然”互换; 第三步,变换联词:“肯定联词”与“否定联词”互换。
MBA逻辑题型总结
虽然MBA逻辑试题千变万化,但万变不离其踪,经仔细研究和全面比较历届考题,发现大部分试题类型是不断重复出现的,从中可以断定MBA逻辑试题确实存在着一定的套路,这里把历届考题按题目的表现形式或解题方法划分为十八种基本套路。如果考生能熟练掌握这些套路特点,在遇到同类问题时,一定有助于尽快理清思路,找到正确答案,从而在考场上能得心应手。现把MBA
逻辑考试十八套路简介如下(详细介绍及大量例题请参阅复旦大学出版社即将出版的新版《MBA联考300分奇迹》)。
一、直接推断型
这类题型的具体形式是:以题干为前提,要求在选项中确定合乎逻辑的结论;或者,从题干出发,不可能推出什么样的结论。其实,解决这类简单推理或直接推断型考题,考生只需运用日常逻辑推理就可以找到答案,几乎没有什么技巧可言,这类题型中很多属于送分题,一般可在十秒中内解决。
二、综合推断型
此类考题表面无统一特征,只是比直接推断型要复杂些,当然所谓复杂,其实并不很复杂,只是要多绕些弯而已。这种试题通常在题干中给出若干条件,要求考生从这些条件中合乎逻辑推出某种结论。这类题型很多涉及复合判断推理,特别是对假言、联言和选言等推理的综合运用。
三、对当关系型
直言判断及对当关系是最基本的一个逻辑知识点(这里,我们把模态命题及其推理也归入其中)。这类试题的表现形式可以多种多样,但近几年在MBA逻辑考试中出现的次数有减少的趋势。解这类题型,要注意的是解题时千万不能以个人经验或专业知识为依据,关键是一定要从题干给出的内容出发,从中抽象出同属于对当关系的逻辑形式,根据对当关系来分析判断。
四、加强支持型
在MBA逻辑考试中,围绕前提和结论之间的支持或反驳关系,设计了多种形式的考题,主要有加强前提型和削弱结论型。加强支持型考题解题思路是,要注意寻找与题干一致的选项。而如果是最不能加强型,当然与题干相矛盾或不一致的选项就最不能加强了。应该说,加强支持型和削弱质疑型是密切相关的,不论加强还是削弱,题干的选项都必须首先与题干相关,紧扣题干,与题干不相干、不一致的选项都不能加强题干,也不能削弱题干。
五、削弱质疑型
削弱质疑型是MBA逻辑考试的一个重点,归结为此类题型的考题是数量是最大的。削弱题型的解题关键是首先应明确原文的推理关系,即什么是前提,什么是结论;在此基础上,寻找削弱的基本方向是针对前提、结论还是论证本身。具体对不同的情况有不同的处理,比如:类型一,直接反对原因,即直接说明原文推理的前提不正确,就达到推翻结论的目的;类型二,指出存在其他可能解释,原文以一个事实、研究、发现或一系列数据为前提推出一个解释上述事实或数据的结论,要削弱这个结论,就可以通过指出由其他可能来解释原文事实;类型三,原文认为A不是导致B的原因,要对其进行削弱,就可以指出A是B的间接原因,即指出A通过导致C而间接的导致了B。
六、传递排序型
传递排序型其实是MBA逻辑考题中比较简单的一种类型,这类题型一般在题干部分给出不同对象之间的若干个两两对比的结果,要求从中推出具体的排序。解这类题型的主要思路是要把所给条件抽象成最简单的排序形式。
七、数字陷阱型
数字陷阱型考题出现的也不少,隐藏在“精确”数字背后的陷阱有如下几种:一是平均数陷阱,在对平均数的模糊理解做文章;二是百分比陷阱,一般题干仅提供两种事物的某种比率就比较出两种事物的结果,其实其陷阱就在于该百分比所赖以计算出来的基数是不同的;三是错误比较,或者不设定供比较的对象,不设定比较的根据或基础,因此,表面上在进行比较,实际上根本就不能比较。
八、真话假话型
把这类考题根据题目的表现形式归结为真话假话型,这是一种通俗的说法,其本质是涉及了逻辑基本规律(同一律、矛盾律、排中律)。解决这类问题的突破口往往是运用对当关系等逻辑知识在所有叙述中找出有互相矛盾的判断,从而必知其一真一假。要注意的是:有时两个命题虽然不是矛盾的,但互相反对(或下反对),即不能同真(或不能同假),那就可以推出两个判断中至少有一个是假的(或者至少有一个是真的),这也同样是解题的关键。值得注意的是,因为前8次考试中,多次出现此题型,但最新考试中已不见了它的踪影。不过,考生仍应多加兼备,因为此类考题实在是容易命题。
九、假言推理型
假言命题及推理型考题,主要是考察充分条件和必要条件的区分及具体运用,这是逻辑考试中一个常考的点。具体要熟悉:(1)推理的传递性(A推出B,B推出C,则A能推出C);(2)不可逆性(重要的考点,A推出B,B真,推不出A真);(3)逆否命题(A推出B,则非B推出非A)。如果已知条件很多很乱的问题时,要迅速找到答案有一定的难度,因此,要同时考虑已知条件和选项,在理解了已知条件的基础上迅速浏览选项,从两头推理,从而尽快找到答案。
十、集合重合型
可以根据基本的集合概念和逻辑常识解决该类题型,解这种题型的重点放在集合的“部分与全体”上,同时要善于分辨可能重合的部分和绝不会重合的部分。最直观的办法是根据题干提供的条件画个小图,题目即可迎刃而解。
十一、寻找假设型
由于这种题型是题干推理中的前提不足够充分以推出结论,要求在选项中确定合适的前提,去补充的原前提或论据,从而能合乎逻辑地推出结论或有利于提高推理的证据支持度和结论的可靠性。因此,做这类题的基本思路是紧扣结论,简化推理过程,从因果关系上考虑,从前提到结论,中间一定有适当的假设,寻找断路或是因为“显然”而省略掉的论述,也就是要“搭桥”,很多时候凭语感或常识就可以找到所要问的隐含的前提。
十二、说明解释型
说明解释型考题也是一种重要的题型,其主要表现形式是,在题干中给出某种需要说明、解释的现象,再问什么样的理由、根据、原因能够最好地解释该现象,或最不能解释该现象,即与该现象的发生不相干。解这类题型有时需要一些相关的背景知识,但这些知识都属于语言常识和一般性常识,并且已经在题干或选项中给出,只是要求从中做一些选择和判断而已。
十三、语义分析型
语义分析型考题在逻辑考试中也比较常见。解这类题的基本思路:一是要阅读仔细,通过对选项和题干的内容逐一对照,从迅速发现找到答案的线索;二是,充分运用自己平时积累起来的语感,力求准确理解、分析和推断题干给出的日常语言表达的句子或内容的复杂含义和深层意义。
十四、匹配逻辑型
匹配逻辑型题型一般特点是,这类题型题干一般提供几类因素,每类因素又有几种不同情况,同时题干还给出属于不同类因素之间不同情况的判断,要求推出确定的结论。有的考生特别害怕这种匹配类型的题目,其实只要细心得法,这类题目并不难。解这类考题时,所要使用的推理形式和推理步骤较多,推理过程显得相对复杂。解题基本思路是,通过对题干给出的多种因素间的关系进行分析推理和排列组合,弄清题干中所给条件的内在关系,从一个一个条件出发,逐步推理,直至推出正确答案。具体比如可以用假设反证法,耐心点推是个笨办法,但绝对是个好办法;也可以用表格法,把已知条件划在一个表格上,再进一步推理。
十五、因果关系型
因果关系及因果倒置型在MBA逻辑考试中出现的形式有多种,比如,为了检查的某种因果关系是否为真,最可靠的实验方法是改变原因后,看结果是否不同,即进行对比实验,对比实验的关键是让实验对象的其他方面的条件相同。又比如,有时两组数据之间的数据因果并不一定有原理因果,可能两组数据都是由其它某一种数据决定的,这就是所谓表面因果与事实因果不符。
十六、逻辑错误型
逻辑错误型考题较多地出现在早期的逻辑考试中,近来有减少的趋势。因为在大纲中已规定“不考察逻辑学的专门知识”,所以,直接判断逻辑错误的考题今后应该不会再出现。今后,今后要考对逻辑错误的辨析,也只能考逻辑错误的类比,比如问你“题干中所犯逻辑错误与下列备选项中的哪一项最为类似?”也就是让考生比较题干和选项中所犯逻辑错误的相同或不同。
十七、形式比较型
形式比较型考题是主要从形式结构上比较题干和五个选项之间的相同或不同,即比较几个不同推理在结构上的相同或者不同。其解题基本思路是,着重考虑从具体的、有内容的思维过程的论述中抽象出一般形式结构,即用命题变项表示其中的单个命题,或用词项变项表示直言命题中的词项,每一个推理中相同的命题或词项用相同的变项表示,不同的命题或词项用不同的变项表示。做这类题型只考虑推理结构和形式,而不考虑其内容的对错,一种出题方式就是题干本身的推理是错误,来对你造成一定的思维困难。
十八、确定论点型
确定论点型的具体表现形式是给出一段文字或对话,要求总结它们所表达的中心内容是什么或什么内容没在题干中表达。或给出一段论述,要求推出结论(确定论点型暨继续推论型的变种:我们不可能得出的结论是)。其解题基本思路是对语言的理解,解此类题型主要是要凭语感、常识和日常的逻辑推理能力去寻找隐含的结论或内在的含义。