Exercise 6: Analyzing the Logical Structure of a Complex Argument
Due Date: Thursday, October 10
Proportion of Final Grade: 8%
"Abortion is murder, for it's the killing of an individual with a right to life. But why is that the case? The reason is that abortion is the killing of a genetically human fetus, and a genetically human fetus has a right to life. Some people try to maintain, of course, that a genetically human fetus does not have a right to life, but that view is clearly unsound. In the first place, a genetically human fetus is itself a human being. Secondly, all humans have immaterial immortal souls from the moment of conception onwards, since that is the forthright and unequivocal teaching of the Catholic Church. And so a genetically human fetus must possess an immaterial immortal soul. But anything that possesses an immaterial immortal soul has a right to life. Therefore a genetically human fetus has a right to life, and abortion is indeed murder."
1. The above passage contains five words, or phrases,
that indicate that an inference is being made. Circle each of
those
inference-indicators. (1 point each, for a total of 5 points.)
2. It is very important to get all five inference-indicators right, since otherwise it will be difficult to work out what the argument is. You may want to take a look, then, at the lecture material on inference-indicators, and to be careful not to mistake such things as argument-indicators, or contrastive terms, or enumerative terms, or assertion terms, for inference-indicators.
3. Each inference involves two premises - one of which may be implicit, rather than being explicitly stated. In the case of each of the five inferences, set out the two premises, and the conclusion. (1 point for each correct premise, and for each correct conclusion, for a total of 15 points.)
4. In attempting to work out the logical structure of the
argument, make full use of the inference-indicators by (1) asking
yourself which of the two types of inference-indicators one has - Is
the inference indicator of the “therefore” type, or of the “since”
type? - and then (2) looking for one of the premises, and the
conclusion, in the appropriate
locations, relative to the inference-indicators, given the type
of inference-indicator in question.
One Way to Check Your Answer
The above passage contains five inferences, each of which involves two premises and a conclusion. If you have correctly identified the two premises and the conclusion in all five cases, it will be possible to arrange the five arguments so that they form a chain of reasoning in which every conclusion, except for the very last one, functions as a premise in the next argument. (Arranging the five arguments in that way is optional. But if you do try to do this, it's important to realize that the order in which the five arguments have to be arranged may be quite different from the order in which they're set out in the above passage.)
Inference 1
Premise 2:
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Conclusion:
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Inference 2
Inference-indicator:
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Premise 1:
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Premise 2:
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Inference 3
Inference-indicator:
________________________________________
Premise 1:
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Premise 2:
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Inference 4
Inference-indicator:
________________________________________
Premise 1:
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Premise 2:
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Inference 5
Inference-indicator:
________________________________________
Premise 1:
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Premise 2:
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