Modes of reasoning Questions 3
lazy808
ExercisesforInductiveAbductiveArguments.ppt“Reasoning About Social Issues”
Petrenko Anton, PhD
Hours: By appointment (Monday 11:30-12:30)
E-Mail: [email protected]
AP/MODR1730 D
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My neighbour must have lost his job. He was home three days last week.
1. The initial observations, prompting the explanatory hypothesis are true (plausible)
2. Testability: The explanation allows to draw testable predictions
3. Scope and Fruitfulness: The explanation explains as many or more observed facts as alternatives, and it explains more diverse phenomena than the alternative
4. Simplicity: The explanation relies on fewer unproven claims or assumptions
5. Conservatism: The explanation fits with existing (confirmed) knowledge.
Abductive Argument
6. Compare an explanation to other possible explanations.
Incidents of violence among people twelve through twenty-one have been increasing over the past twenty years. During that same period, The Simpsons has become one of the most popular TV shows among people in that age group. By teaching a disrespect for authority, The Simpsons is clearly contributing to the rise in violence.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
Causal Argument
We cannot blame men or women for sexual infidelity. Recent research has shown that animals cheat sexually all the time. Why should the situation be any different with humans? Female animals look for males who show signs of biological fitness, and will mate with such a male even if they are already bonded with another male. The same is also true of male animals. Just so it is with humans. As we should not blame animals for sexual infidelity, neither should we blame human beings for sexual infidelity.
1. Truth of the reasons: are the two things compared similar in the required way?
2. Are the known similar properties relevant to the property one is trying to infer?
3. How high is the number of similar characteristics (the higher, the stronger the analogy).
4. How varied are the shared characteristics (the greater variety of similar characteristics, the better)
5. Are there any significant disanalogies (or dissimilarities) that cast doubt on the conclusion?
Argument from Analogy
We cannot blame men or women for sexual infidelity. Recent research has shown that animals cheat sexually all the time. Why should the situation be any different with humans? Female animals look for males who show signs of biological fitness, and will mate with such a male even if they are already bonded with another male. The same is also true of male animals. Just so it is with humans. As we should not blame animals for sexual infidelity, neither should we blame human beings for sexual infidelity.
- Truth of the reasons: are the two things compared similar in the required way?
Are the initial observation true? There is evidence that some animals are monogamous (e.g. some birds that mate for life), while other animals are polygamous, and some animals are monogamous temporarily. So, it is not true that all animals are polygamous. However, it is true that some animals will mate outside the relationship. It is true that some human beings do that as well. It is true that both can be attracted by signs of biological fitness.
2. Are the known similar properties relevant to the property one is trying to infer?
The similarity is that both humans and animals are biological species subject to evolutionary pressures. Is this relevant to the inference of moral blamelessness. It is somewhat relevant—if humans are predetermined by biology to cheat than one cannot hold it morally against them.
3. How high is the number of similar characteristics (the higher, the stronger the analogy).
Humans and other animals are biological species. They can engage in cheating. According to biology they are both subject to evolutionary pressures. Both look for signs of biological fitness. There are many similarities.
4. How varied are the shared characteristics (the greater variety of similar characteristics, the better)
The similar characteristics mostly have to do with the common basic biological nature that humans and animals share: bonding, mating, looking for biological fitness.
5. Are there any significant disanalogies (or dissimilarities) that cast doubt on the conclusion?
There are serious disanalogies that undermine the analogy. Human beings have intelligence that allows them to rise above biological impulses and reflect on their choices. They are capable of rational choice. Human beings also have moral norms about right and wrong that animals lack. Because human beings can be motivated by moral reasons and make moral choices they can be held responsible for their actions (unlike animals that are controlled by their biology)
Argument from Analogy
The theory of evolution was not widely taught in American schools until 1963, with the
introduction of new biology textbooks. Throughout the 1950s, there was little social upheaval and disorder in American society. Everyone knew the rules for a well-ordered society and followed them. Immediately after the widespread teaching of evolutionary theory, society disintegrated into chaos—crime rates rose; blacks, women, adolescents began challenging all authority and engaging in violent protests; pornography became rampant; abortion became legal; illegitimacy rates rose
dramatically. It is clear that teaching evolutionary theory destroys any sense of morality.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
The theory of evolution was not widely taught in American schools until 1963, with the introduction of new biology textbooks. Throughout the 1950s, there was little social upheaval and disorder in American society. Everyone knew the rules for a well-ordered society and followed them. Immediately after the widespread teaching of evolutionary theory, society disintegrated into chaos—crime rates rose; blacks, women, adolescents began challenging all authority and engaging in violent protests; pornography became rampant; abortion became legal; illegitimacy rates rose dramatically. It is clear that teaching evolutionary theory destroys any sense of morality.
- Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
Temporal priority is not clearly established. It is not clear from the evidence when exactly the social upheavals began. There is reason to doubt that they started precisely after the introduction of evolutionary theory in textbooks—bitniks, mods, bikers in US were challenging authority before that date.
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
There is no evidence of covariation—only loose evidence of correlation. We do not have evidence that if evolutionary theory is remved from the books it restores moral values or eliminates social protest. We only have information that loosely at the same time as evolutionary theory was introduced, there were social upheavals and protests.
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
The author seems to suggest that lack of faith in God led to lack of believe in moral right and wrong. Theoretically, it is possible that in a society where the right and wrong is grounded in the believe in God, loss of faith might undermine confidence in moral values. Although it is conceivable, there are many atheistic societies who hold strong believes in right and wrong (communism, secular civil societies)
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
There are no controls on other factors. The civil rights movement, antiwar protests, and challenges to the past social and moral arrangement could be due to the spread of post war liberal ideas, the growth of the younger, baby boomer generation with their own ideas about social justice, and growing US prosperity that enabled younger generations to be concerned moral and civil rights rather than just survival. Even bigger problem in the argument is the view that civil rights protests represent a collapse of morality, rather than its growth. Its likely the protesters were concerned with moral questions more than previous generations.
The number of people killed or severely injured by guns and gun-related crimes has increased by ten percent in each of the past three years. We can look forward to another increase of ten percent this year.
1. It is based on evidence or observations of a number of cases.
2. The observations are systematic (not anecdotal)
3. The sample and the population are easily identified.
4. The sample is representative of the population (reflects variability and frequency)
5. The generalization does not over-generalize the sample in relation to the population—it has an adequate scope (sample is large enough for the scope).
Inductive Generalization (Statistical Syllogism)
1. It is based on evidence or observations of a number of cases.
2. The observations are systematic (not anecdotal)
3. The sample and the population are easily identified.
4. The sample is representative of the population (reflects variability and frequency)
5. The generalization does not over-generalize the sample in relation to the population—it has an adequate scope (sample is large enough for the scope).
Inductive Generalization
Four of the major leaders of modern evolutionary theory—Richard Dawkins, author of The Selfish Gene; Francis Crick and James Watson, who together won the Nobel Prize for discovering the structure of DNA; and E. O. Wilson, founder of sociobiology—are not only atheists but argue that evolutionary theory shows that religion is not only unnecessary but harmful. It is clear both that evolutionary theory is atheistic and that biologists are atheists.
- It is based on evidence or observations of a number of cases.
The generalization is based on a very small (sample) number of cases (relative to the population)—specifically, four authors.
2. The observations are systematic (not anecdotal)
The observation of the relevant property, that they are all atheists with strong view against religion, is anecdotal rather than systematic. No criteria is established to categorize authors into atheists and what qualifies as being against religion. The criteria are not specified and might be subject to personal interpretation.
3. The sample and the population are easily identified.
The sample are the four authors that are listed. The population is also somewhat clear—it is all (evolutionary) biologists.
4. The sample is representative of the population (reflects variability and frequency).
The sample is not representative of the population because the authors are not chosen randomly. They were chosen because of their fame, which might be a result of their critical views. Choosing on such basis introduces bias into the sample—thus sample fails to include variety present in the population of biologists by failing to include biologists who have less critical views (religious biologists). It also fails to represent their frequency in the population.
5. The generalization does not over-generalize the sample in relation to the population—it has an adequate scope (sample is large enough for the scope).
The sample also fails on being of adequate size. It consist only of four biologists but it generalizes to all biologists (likely numbering in thousands). This is an overgeneralization. The scope of the conclusion would be more adequate to the sample size if it clamed that “some biologists are atheists.”
Inductive Generalization
Four of the major leaders of modern evolutionary theory—Richard Dawkins, author of The Selfish Gene; Francis Crick and James Watson, who together won the Nobel Prize for discovering the structure of DNA; and E. O. Wilson, founder of sociobiology—are not only atheists but argue that evolutionary theory shows that religion is not only unnecessary but harmful. It is clear both that evolutionary theory is atheistic and that biologists are atheists.
It is cruel to encourage the suffering of unwanted and abandoned puppies and kittens.
That is why we spay or neuter our pets. But surely people are more important than pets, and the suffering of an unwanted and abandoned child is far worse than the suffering of a dog or cat. If we sterilize our pets to prevent suffering, then we can surely do no less for the poor and homeless.
1. Truth of the reasons: are the two things compared similar in the required way?
2. Are the known similar properties relevant to the property one is trying to infer?
3. How high is the number of similar characteristics (the higher, the stronger the analogy).
4. How varied are the shared characteristics (the greater variety of similar characteristics, the better)
5. Are there any significant disanalogies (or dissimilarities) that cast doubt on the conclusion?
Argument from Analogy
There were three food-product recalls yesterday. I checked and found there has been an average of one a day for the past year. Ten years ago, there was an average of one every ten days. The average number of recalls has been increasing steadily over the past ten years, but they have particularly escalated in the past three years. It seems that our food system is far less safe than it was
ten years ago, despite increased regulation and monitoring.
1. The initial observations, prompting the explanatory hypothesis are true (plausible)
2. Testability: The explanation allows to draw testable predictions
3. Scope and Fruitfulness: The explanation explains as many or more observed facts as alternatives, and it explains more diverse phenomena than the alternative
4. Simplicity: The explanation relies on fewer unproven claims or assumptions
5. Conservatism: The explanation fits with existing (confirmed) knowledge.
Abductive Argument
6. Compare an explanation to other possible explanations.
There were three food-product recalls yesterday. I checked and found there has been an average of one a day for the past year. Ten years ago, there was an average of one every ten days. The average number of recalls has been increasing steadily over the past ten years, but they have particularly escalated in the past three years. It seems that our food system is far less safe than it was ten years ago, despite increased regulation and monitoring.
- The initial observations, prompting the explanatory hypothesis are true (plausible)
There is no reason to doubt the truth of the initial observations in this case—these are given by the author and we have no way of checking it or scrutinize their truth. We can assume the person is not lying.
2. Testability: The explanation allows to draw testable predictions
Potentially it is possible to test this hypothesis. We could determine the amount of food produced in the past and now, establish criteria for safety, and examine if a greater % of food based on the same criteria is found to be unsafe now than in the past.
3. Scope and Fruitfulness: The explanation explains as many or more observed facts as alternatives, and it explains more diverse phenomena than the alternative
The explanation that food is becoming less safe can explain the increased recalls. However, it does not explain why the increase comes despite increased regulation. If regulation increases, the food should become safer. Scope is narrower than possible.
4. Simplicity: The explanation relies on fewer unproven claims or assumptions
The explanation assumes that food is becoming less safe to explain increased recalls. But it assumes it without explaining why it is becoming less safe—we have no independent explanation why it becomes less safe. So, the explanation is not as simple as it could be—it makes an assumption.
5. Conservatism: The explanation fits with existing (confirmed) knowledge.
The explanation fits with well confirmed knowledge—food production can in principle become less safe
Abductive Argument
6. Alternatives: It is possible that recalls are increased because the regulation have increased and so the standard of what counts as safe food have changed over time by becoming more demanding. This explanation is testable (check food criteria) It has wider scope (explains recalls and increased regulation), simpler (makes no unexplained assumptions about decreased food safety, and equally conservative (maybe more because since normally increased regulation improves food safety). Alternatively, it is possible that the amount of food produce overall has increased—recalls have increased due to greater food production but relative numbers of unsafe food might be falling.
Whenever I visit my sisters in Ontario and Quebec in the summer, my allergies go crazy. I never have any trouble in B.C. or Alberta. There must be something about the different plants in these provinces that provoke my allergies. I’ve got to stay away from Ontario and Quebec in the summer.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
Society is a survival of the fittest. Just as in nature the weak do not and should not survive, so too in society. If the weak in society cannot survive without societal (government) support, then there is no obligation on the part of society to ensure their survival. If the poor, the disabled, the aged, cannot survive on their own, then there is no obligation on the part of society to ensure their survival.
1. Truth of the reasons: are the two things compared similar in the required way?
2. Are the known similar properties relevant to the property one is trying to infer?
3. How high is the number of similar characteristics (the higher, the stronger the analogy).
4. How varied are the shared characteristics (the greater variety of similar characteristics, the better)
5. Are there any significant disanalogies (or dissimilarities) that cast doubt on the conclusion?
Argument from Analogy
The incidence of syphilis has gone up in the past five years. At the same time, the teaching of sex education has moved from the upper grades to grades eight and nine. To stop the spread of syphilis, we have to stop teaching sex education.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
Three times last semester, the university administration allowed both the Palestinian and Israeli student organizations to set up information tables in the Student Centre. Each time, there were outbreaks of violence. I don’t think we should allow them to have information tables in the Student Centre this term.
1. It is based on evidence or observations of a number of cases.
2. The observations are systematic (not anecdotal)
3. The sample and the population are easily identified.
4. The sample is representative of the population (reflects variability and frequency)
5. The generalization does not over-generalize the sample in relation to the population—it has an adequate scope (sample is large enough for the scope).
Inductive Generalization (Statistical Syllogism)
Fatima’s car was found unlocked and parked by the side of the road. The keys were in the ignition. Her purse and cell phone were untouched inside the car. Last week, two other people disappeared in the same area. Then two days later, they turned up and reported that they had been abducted by aliens. There have been two other such cases in the area in the past six months. Fatima was obviously abducted by aliens.
1. The initial observations, prompting the explanatory hypothesis are true (plausible)
2. Testability: The explanation allows to draw testable predictions
3. Scope and Fruitfulness: The explanation explains as many or more observed facts as alternatives, and it explains more diverse phenomena than the alternative
4. Simplicity: The explanation relies on fewer unproven claims or assumptions
5. Conservatism: The explanation fits with existing (confirmed) knowledge.
Abductive Argument
6. Compare an explanation to other possible explanations.
Green tea may help prevent cancer. A recent study of five thousand people, half of whom have been drinking at least three cups of green tea daily for twenty years or more compared to the other half, who drink coffee or black tea, has shown there is twenty percent less incidence of stomach and esophageal cancer in the green tea drinkers. Researchers have recently isolated a chemical in green tea that acts to inhibit the growth of cancer tumours in mice.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
The national debt is like a metastasizing cancer that threatens to destroy our economy from within. We must take whatever measures are necessary to stop this cancer from threatening the life of society.
1. Truth of the reasons: are the two things compared similar in the required way?
2. Are the known similar properties relevant to the property one is trying to infer?
3. How high is the number of similar characteristics (the higher, the stronger the analogy).
4. How varied are the shared characteristics (the greater variety of similar characteristics, the better)
5. Are there any significant disanalogies (or dissimilarities) that cast doubt on the conclusion?
Argument from Analogy
After two years of disappointing performances and rained-out sessions, the last four
Montreal Jazz Festivals have been huge successes. Since the weather is supposed to be good this year, I expect that this year’s will also be a huge success.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
My three best friends all took economics and got great jobs upon graduation. Even though I am not great at math, I had better take economics. It will lead to a great job.
1. Temporal priority: event A (the alleged cause) always precedes event B (the alleged effect).
3. Covariance: The two events must vary together; as one varies (e.g. increases or decreases), the other also varies (increases or decreases).
Causal Argument
2. Reasonable mechanism (spatial connection): a reasonable mechanism should be conceivable that enables the causal relation between two events (intervening cause).
4. Have other possible causes (other potential causal factors) been ruled out (controlled)?
