Lesson review Unit



Part6A: Categorical syllogism, mood, form and figure

Syllogismsare two premises and a conclusion. There is also another from calledcategorical syllogism where the premises are categorical. Incategorical syllogisms, there are three main terms minor, middle andmajor. Minor term appears once in premise and once in conclusion asthe subject. The middle term links the minor and major terms in theconclusion. Syllogism is considered standard if the major premisefalls first followed by minor premise and the conclusion. Theordering helps determine the mood of the sentence. In standard formcategorical syllogisms, where the middle terms appears is expected.In other syllogism forms, the place is undetermined and thus affectsthe mood of arguments in a sentence. Mood of argument here is definedas the order of sentence types when syllogism is in standard form orsimply order of sentence types in an argument.

Thereare different moods of argument that can be used in sentences asexpressed by the present vowels. For instance the AAA type implies an“a” premise followed by another “A” premise and an “A”conclusion. The sentence type and their structure in the premisesalso determine their validity. The moods are grouped into fourfigures denoting places where the middle term could show up insentences. There are several main valid moods categorized into figure1, 2, 3 and 4. For instance, under figure one, the three main validmoods are AAA, AOO and OAO. The grouping helps determine the validityof the arguments.

Thesemoods can be memorized in an inventory using Latin words. The EIOmood is unique in the sense that it is valid in all the four figures.The phrase “Barbara’s neighbors maiming feared” can helpmemorize the valid moods in figure 1 by denoting the sequence ofvowels in the words (AAA, EAE, AII, EIO). The second phrase is“Alfonso’s feared careers can help memorize valid moods in figure2 (EAE, AEE, EIO &amp AOO). The third phrase “Orlando’sneighbors distain maiming” and “distain careers 4 neighbors”captures the moods in figure 3 and 4.

6B:formal logic: Venn diagrams explained

Thissecond video of the crash course explains Venn diagrams in verysimple ways. Venn diagrams are basically shows allpossible logical relationships between a predetermined collection ofsets. Inmost cases, three sets are sets are used depicted in threeoverlapping circles. The different circles represent the two premisesand one conclusion. There are four main area created by theoverlapping circles while three areas remain intact. Of the fourareas of interacting circles, three of them represent interactionsdifferent combinations of interactions between two different circleswith only one representing the overlapping of the three circles. Itis this central area comprising of the three circles that capturesthe relevant and valid argument. Aristotle also noted that if thereis no universal premise, the argument is invalid and thus noconclusion can be drawn. Additionally, if in case of diagrammingarguments on the Venn diagram and one is not sure of what the clearconclusion is, then the argument may be invalid. Simply put, if thepremises are correct and the conclusion incorrect, then the argumentas a whole is invalid. The Venn diagram comes in handy is mapping inidentifying valid and invalid arguments. Any presence of floating xas explained in the lesson is as indicator of an invalid argument.

6C:Rules for Categorical Syllogisms

Thisis the third video of the crash course on syllogism. It explains therules for categorical syllogisms after learning about there being twotypes of syllogisms, categorical and standard. There are four mainrules on distribution and quality of propositions. Quality can beaffirmative of negative while distribution can be subject, both noneor predicate. The first rule on distribution is that if the predicateis distributed in the conclusions, it should be distributed in thepremises. Second rule of distribution states that the premises mustdistribute the middle term at least once. On quality, the first ruleis that no conclusion can be obtained from two negative premises. Forexample “no lades are gentlemen” and “some humans are notladies” cannot produce any sensible conclusion because the twopremises are negative. The second rule still on quality reads thatone negative premise can only lead to a negative conclusion. Forinstance, a “all NBA players are athletes” and “all athletesare not healthy people” can only give out a negative conclusionpossibly to say that “some NBA players are not healthy”. Thisrule also means that a positive conclusion can only be obtained fromtwo positive premises.

Ifind the lesson on Rules for Categorical Syllogisms as the most funand easiest to understand and follow. The lesson is also moreinteresting given the many examples used. I also found it easy toapply the examples on my own unlike in the other cases. I must alsocommend the instructor on the simplification of the formula to recallmoods. I must admit that the Latin formula is scary for students andappears irrelevant. All in all, I feel better equipped in handlingsyllogism. I am sure after practicing the different formulas andstrategies taught in the three lessons I will be better equippedsyllogisms.


https://www.youtube.com/watch?v=KcNESCrkIiQ6thNov 2014. nd. Web

https://www.youtube.com/watch?v=to6kEzy17cM6thNov 2014. nd. Web

https://www.youtube.com/watch?v=fp3-DWh24eI6thNov 2014. nd. Web