開場白
推動一項新決策時，沒有人反對，是好事嗎？ 眾人構思假設時，只得出 1 個假設，是好事嗎？
構思假設
下面 4 張圖表，說明假設的構思和分析過程。類研究猿教偵查時的證據分析曾介紹過。教材來自 Randolph H. Pherson 和 Richards Heuer Jr. 的 Structured Analytic Techniques for Intelligence Analysis。
圖 1： 構思假設
圖 2：每名偵查員對競爭性假設分析
圖 3：總結所有偵查員對競爭性假設分析
圖 4：偵查員的共通言語
以色列的教訓
1967 年 6 月，第三次中東戰爭（又稱六日戰爭、六月戰爭），在短短六日，以色列攻佔了：
- 整個西奈半島至蘇伊士運河的停火線；
- 大約一半的敘利亞的戈蘭高地。
以色列領土擴大了 3 倍。埃及和敘利亞都想拿回失去的土地。
1973年，第四次中東戰爭（又稱贖罪日戰爭、齋月戰爭、十月戰爭），埃及和敘利亞經周密准備對以實施戰略突襲。戰爭的前 2 日埃敘聯盟佔了上風。至第 2 周，敘軍退出戈蘭高地；在西奈半島，以軍殲滅了一隊埃及軍隊。直到聯合國停火令生效為止，以色列在遭到突然襲擊的被動局勢下，一舉翻盤。
以色列情報工作的失誤是導致戰爭初期慘敗的主要原因。 以色列吸取了教訓，進行了情報改革。Yosef Kuperwasser 的 Lessons from Israel’s Intelligence Reforms 說：
First, in order to make sure that different and opposing opinions are heard within the Israeli intelligence community, AMAN has a culture of openness, where individuals are expected to voice dissenting opinions. The organizational slogan that reflects this openness is, “Freedom of opinion, discipline in action.” AMAN has two other tools that promote diversity: the “devil’s advocate” office and the option of writing “different opinion” memos.
The devil’s advocate office ensures that AMAN’s intelligence assessments are creative and do not fall prey to group think. The office regularly criticizes products coming from the analysis and production divisions, and writes opinion papers that counter these departments’ assessments. The staff in the devil’s advocate office is made up of extremely experienced and talented officers who are known to have a creative, “outside the box” way of thinking. Perhaps as important, they are highly regarded by the analysts. As such, strong consideration is given to their conclusions and their memos go directly to the office of the Director of Military Intelligence, as well as to all major decision makers. The devil’s advocate office also pro-actively combats group think and conventional wisdom by writing papers that examine the possibility of a radical and negative change occurring within the security environment. This is done even when the defence establishment does not think that such a development is likely, precisely to explore alternative assumptions and worst-case scenarios.
While the devil’s advocate office is an institutional level safeguard against group think, there is also an individual-level safeguard. The analysts themselves are given venues for expressing alternate opinions. Any analyst can author a “different opinion” memo in which he or she can critique the conclusions of his or her department. Senior officers do not criticize analysts who choose to write such memos.
簡而言之，以色列國防部專門成立了一個機構，號稱魔鬼代言人，他們以各種方式挑戰情報機構做出的普遍假設。不管前人的結論看起來多麼正確，多麼萬無一失，他們必須提出異議，探索不同假設和最壞情況，並將意見直接送給軍事情報局局長辦公室，防止團體盲思及單一指揮官壟斷意見。
這個方法後來被意譯為「第十人理論」。大多數（9 個人）人認為事情是對的時候，第 10 個人要嘗試從反面角度看待問題，那才可以找出隱憂，全面考慮問題。
電影「地球末日戰」World War Z
2013 年上映的電影「地球末日戰」中，以色列政府提出了的「第十人理論」：
If nine of us with the same information arrived at the exact same conclusion, it’s the duty of the tenth man to disagree. No matter how improbable it may seem, the tenth man has to start thinking with the assumption that the other nine were wrong.
魔鬼代言人可以不足之處
Randolph H. Pherson 和 Richards Heuer Jr. 不支持這種做法，原因之一是：
Research shows that a person playing the role of a Devil’s Advocate, without actually believing it, is significantly less effective than a true believer and may even by counter-productive. Apparently, more attention and respect is accorded to someone with the courage to advance their own minority view than to someone who is known to be only playing a role. If group members see the Devil’s Advocate is an analytic exercise they have to put up with, rather than the true belief of one of their members who is courageous enough to speak out, this exercise may actually enhance the majority’s original belief - “a smugness that may occur because one assumes one has considered alternatives though, in fact, these has been little serious reflection on other possibilities.” What the team learns from the Devil’s Advocate presentation may be only how to better defend the team’s own entrenched position.
以色列通過組織和程序結構，解決了上述問題。
Randolph H. Pherson 和 Richards Heuer Jr. 認為可以用以下方法代替魔鬼代言人：
- 有條理的進行自我批評；
- 假設分析；
- 高影響/低概率分析。
類研究猿以後會介紹。
類研究猿也會介紹一下國外的調查不到位案例。
收場白
Secretary Colin L. Powell, Opening Remarks before the Senate Governmental Affairs Committee, Washington, DC, September 13, 2004:
Tell me what you know. Tell me what you don’t know. And then, based on what you really know and what you really don’t know, tell me what you think is most likely to happen. And there’s an extension of that rule with my intelligence officers: I will hold you accountable for what you tell me is a fact; and I will hold you accountable for what you tell me is not going to happen because you have the facts on that, or you don’t know what’s going to happen, or you know what your body of ignorance is and you told me what that is.
Now, when you tell me what’s most likely to happen, then I, as the policy maker, have to make a judgment as to whether I act on that, and I won’t hold you accountable for it because that is a judgment; and judgments of this kind are made by policy makers, not by intelligence experts.