GMAT邏輯推理錯誤解析之假設(shè)篇(一).

　　GMAT邏輯推理中的假設(shè)題型作為一類?？碱}型有著非常重要的意義，往往在考試時(shí)，考生卻不知道應(yīng)該如何有效找到可以使得整個推理成立的必要條件，或者考生往往出于使推理一定正確的心理，在各個選項(xiàng)中游走不定，最終導(dǎo)致考生無法清楚到底哪個選項(xiàng)才是“真正”的符合題干要求的推理?xiàng)l件。其實(shí)我們在解題的過程中把握一個宗旨，也許我們就會發(fā)現(xiàn)其實(shí)假設(shè)題型并非我們想象的那樣難，這個宗旨就是：只需要找到一個能使得推理成立的條件或者說是必要條件，我們不需要去保證通過這個條件推理一定做到正確。下面就讓我們通過實(shí)例對考生在假設(shè)推理的過程中容易出現(xiàn)的錯誤進(jìn)行解析。

　　無法找出題干中討論對象之間的本質(zhì)關(guān)系

　　例：A thorough search of Edgar Allan Poe’s correspondence has turned up not a single letter in which he mentions his reputed morphine addiction. On the basis of this evidence it is safe to say that Poe’s reputation for having been a morphine addict is undeserved and that reports of his supposed addiction are untrue.

　　Which of the following is assumed by the argument above?

　　(A) Reports claiming that Poe was addicted to morphine did not begin to circulate until after his death.

　　(B) None of the reports of Poe’s supposed morphine addiction can be traced to individuals who actually knew Poe.

　　(C) Poe’s income from writing would not have been sufficient to support a morphine addiction

　　(D) Poe would have been unable to carry on an extensive correspondence while under the influence of morphine

　　(E) Fear of the consequences would not have prevented Poe from indicating in his correspondence that he was addicted to morphine.

　　上述題干中提到：一、研究發(fā)現(xiàn)Poe的信件中未提及他患有嗎啡癮;二、Poe沒有嗎啡癮

　　本題極力在讓考生從“對Poe的信件調(diào)查[證據(jù)]→Poe未患有嗎啡癮[結(jié)論]”找出兩者的內(nèi)在聯(lián)系，5個選項(xiàng)中也給出了不同的假設(shè)，那么我們只需通過反推，來找出一種能夠使得推理成立的假設(shè)條件即可，但考生往往會拋開“信件調(diào)查”去思考其他使得上述結(jié)論正確的條件(假設(shè))，換句話說考生往往會認(rèn)為除了對信件的調(diào)查這樣一個證據(jù)以外，還可以有其他證據(jù)能夠推出Poe未患有嗎啡癮。通常來講，當(dāng)一個推理是從一個我們已知的，已經(jīng)發(fā)生的事實(shí)推斷出一個結(jié)論的時(shí)候，我們需要記住的就是，其中的隱含假設(shè)多為這個結(jié)論的唯一原因，換句話說，在本題中要想對Poe的信件做出說明，那么我們只能假定Poe不會因害怕后果而不在其信件中提及對嗎啡的嗜好，本題的正確假設(shè)選項(xiàng)為E.