Logic midterm CH 1
An argument that proceeds from knowledge of an effect to a claim about a cause is:
An inductive argument.
An argument whose conclusion rests on a similarity between two things or situations is:
An inductive argument.
In the expression "If a nation engages in torture, then it loses moral authority in the world community," the statement "A nation engages in torture" is called the:
Antecedent.
In the expression "If electric cars become popular, then the price of gasoline will drop," the statement "Electric cars become popular" is called the:
Antecedent.
The loss of arctic ice is accelerating as a result of a form of positive feedback. As arctic ice melts, the arctic icecap reflects fewer rays from the sun. When this happens, more rays are absorbed by the surrounding ocean, which increases its temperature. As the temperature of the ocean rises, more arctic ice melts.
Argument; conclusion: The loss of arctic ice ... positive feedback.
In the expression "The moon sends forth light because it reflects light from the sun," the statement "The moon sends forth light" is called the:
Explanandum.
In the expression, "Carbon monoxide is poisonous because it prevents hemoglobin from supplying oxygen to the body," the statement "Carbon monoxide is poisonous" is called the:
Explanandum.
As the universe expands, it gets colder and colder. Furthermore, this expansion will continue for ever and ever. Therefore, at some point in the future the universe will become too cold to support human life, and all humans will perish.
Inductive, strong.
James Bloomfield, the widely respected expert on art authentication, says that the painting recently discovered in the basement of the art museum is a genuine Picasso. Therefore, we conclude that the painting is indeed a genuine Picasso.
Inductive, strong.
The arctic ice cap has been shrinking for several years as a result of global warming, and that trend is expected to continue. Therefore, since arctic polar bears depend on that ice for survival, the arctic polar bear population will shrink in the years ahead.
Inductive, strong.
The engraved plate beneath this painting in the art museum says "Monet." Therefore, the painting must be the work of Monet.
Inductive, strong.
A divining rod is a magical device for detecting hidden water, metal, and gemstones. Your friend Roger is using his divining rod on the beach right now. Therefore, he'll likely find some diamonds buried beneath the sand.
Inductive, weak.
After investing in the stock market, Pamela doubled her money in just two years, and Beth and Tiffany did the same thing. However, Greg, Ivan, and Marty all lost money on the stock market during the same time frame. The obvious conclusion is that women do better than men in the stock market.
Inductive, weak.
Astrological calculations indicate that the U.S. stock market will crash in the year 2020. Therefore, you should get your money out of the market before that year.
Inductive, weak.
Canada is similar in many ways to the United States. Both countries share the same language, values, and a free market economy. Also, they share a common border. Therefore, the Canadian flag must look a lot like the U.S. flag.
Inductive, weak.
During the past 80 years, the number of Model T Fords on the highway has steadily fallen while the number of deaths from lung cancer has steadily risen. Thus, to reduce the number of deaths from lung cancer we should bring back the Model T Ford.
Inductive, weak.
Graffiti painted on that vacant building says "Boycott Meat." Therefore, it's clear that we should all become vegetarians.
Inductive, weak.
Jim Searcy, a religious prophet who now lives in Cypress, claims that the Prince of Wales is the Antichrist. Therefore, we must conclude that the Prince of Wales is up to no good.
Inductive, weak.
The poster on your neighbor's lawn says "Vote Horton for Sheriff." Therefore, it's clear that Horton would make a great sheriff
Inductive, weak.
The poster on your neighbor's lawn says "Vote Horton for Sheriff." Therefore, it's clear that Horton would make a great sheriff.
Inductive, weak.
When Jack took his car in for service, the mechanic charged him for lots of work that didn't need to be done. The same thing happened to Niki and Claire. Apparently mechanics these days are just a bunch of crooks.
Inductive, weak.
Properly speaking, which of the following features of an argument is either valid or invalid?
its form
An argument's form is
its relationships of logical ideas and parts
Words like 'because' and 'since' tend to indicate
premises
Which of these may an argument be?
sound
An argument is a collection of statements in which
the premises are intended to support the conclusion
The primary focus of logic is
the structure and evaluation of arguments
Words like 'since' and 'as a result' are significant for us because
they help us identify premises or conclusions
The earth is of interest to astronomy for many reasons. Nearly all observations must be made through the atmosphere, and the phenomena of the upper atmosphere and the magnetosphere reflect the state of interplanetary space. The earth is also the most important object of comparison for planetologists. Hannu Karttunen, et al., Fundamental Astronomy
Argument; conclusion: The earth is of interest to astronomy.
An argument that applies a scientific law to a specific case is usually:
A deductive argument.
An argument whose conclusion rests on some geometrical procedure is:
A deductive argument.
Developing an AIDS vaccine is not impossible, as some skeptics claim. Research suggests that the human immune system is better at fighting HIV than was originally thought. Most of those infected suppress the virus for years without developing AIDS. A small number never contract the virus despite repeated exposures. If we can figure out the mechanism that accounts for this, we'll have clues about how to engineer a vaccine. Seth Berkley, "Don't Quit on an AIDS Vaccine"
Argument; conclusion: Developing an AIDS vaccine ... skeptics claim.
Humans are biological organisms. To understand our behavior and mental processes, we need to understand their biological underpinnings, starting with the cellular level, the neuron. How we feel, learn, remember, and think all stem from neuronal activity. So, how a neuron works and how neurons communicate are crucial pieces of information in solving the puzzle of human behavior and mental processing. Richard Griggs, Psychology: A Concise Introduction
Argument; conclusion: How a neuron works ... mental processing.
It is likely that innocent prisoners in this country have been executed for crimes they did not commit. From 1973 until 2016, 151 death row inmates have been exonerated. In many of these cases DNA evidence played a crucial role. Yet, in that same time frame, more than 1000 prisoners were executed. For many of these prisoners no DNA evidence was available. If such evidence had been available, how may more would have been exonerated?
Argument; conclusion: It is likely that innocent prisoners ... they did not commit.
Undocumented immigrants pay local sales taxes, and many of them also pay state, local, and federal income tax and Social Security tax. They also purchase items from local merchants, increasing the amount these merchants pay in taxes. In addition, they work for low salaries, which increases the earnings of their employers and the amount of taxes these employers pay. Thus, it is not correct to say that undocumented immigrants contribute nothing to the communities in which they live.
Argument; conclusion: It is not correct to say ... communities in which they live
It's even more important these days that your computer be protected by a firewall. There are criminal elements lurking in the shadows of cyberspace who send out probes to detect unprotected PCs. Once a vulnerable computer is found, these criminals install software that assists them in committing identity theft and fencing stolen IDs. They also defraud online advertisers by using these zombie computers to visit pay-per-click ads.
Argument; conclusion: It's even more important ... protected by a firewall.
Prior to their extinction, Neanderthals had been widespread in Europe for 100,000 years. Then 50,000 years ago, modern humans moved into Europe from Africa. Twenty-six thousand years after that the last Neanderthal died. At one time it was thought that the Neanderthals were killed by climate change, but this theory has now been discounted. So why did the Neanderthals perish? Probably they were killed by the humans.
Argument; conclusion: Probably they were killed by the humans.
Scientists may be on the verge of creating life in a test tube. Recently, scientists have used computers to synthesize a highly complex loop of DNA. When this loop was inserted into an empty bacterial cell, the cell began to self-replicate. And self-replication is an essential feature of life.
Argument; conclusion: Scientists may be on the verge ... life in a test tube.
Some over-the-counter medicines should not be given to very young children. For example, cold medicines contain decongestants and antihistamines. These substances raise blood pressure and heart rate. If an overdose should occur in a young child, the result can be fatal.
Argument; conclusion: Some over-the-counter medicines ... very young children.
The world-wide disappearance of frogs may be the result of agricultural runoff. Scientists have shown that runoff rich in fertilizer causes a pronounced increase in the algae of lakes and ponds. Snails then gorge themselves on the algae, causing parasites living inside them to produce huge quantities of eggs. When the eggs hatch, the parasites infect young frogs, causing severe deformation of their limbs.
Argument; conclusion: The world-wide disappearance ... agricultural runoff.
Until recently, it looked as though the loggerhead sea turtle might be making a comeback. But a new federal report suggests that loggerheads have begun to decline again. Their life-pattern makes them doubly vulnerable to humans. They lay their eggs on beaches, habitat vulnerable to development and disturbance, and they spend their long lives at sea, where they are often fouled in fishing nets. Newspaper editorial
Argument; conclusion: Their life-pattern ... doubly vulnerable to humans.
There appears to be a growing happiness gap between men and women. Women today are working more and relaxing less, while men are working less and relaxing more. Forty years ago a typical woman spent 40 minutes more per week than the typical man performing an activity considered unpleasant. Today, with men working less, the gap is 90 minutes and growing.
Argument; conclusion: There appears to be ... between men and women.
Good intentions aside, there are compelling reasons to avoid water fluoridation. Hydrofluosilic acid, the industrial waste product used in municipal water systems, is contaminated with arsenic, lead, and other heavy metals. There are significant increases in lead levels in children who drink fluoridated water. A 2015 Harvard study found a fivefold to sevenfold increase in bone cancer in exposed young men. Sadly, the youngest children are the most susceptible. David S. Banks, Letter to the Editor
Argument; conclusion: There are compelling reasons to avoid water fluoridation.
To focus on the performance of the stock market is to zero in on an economic indicator that can do well even as the country does poorly. In 2006, for instance, the Dow Jones industrial average hit highs. According to the just released census data, however, median earnings fell one percent, and millions more Americans entered the ranks of the uninsured. Indeed, from 2000 to 2007 the S&P 500 gained more than 500 points. Meanwhile, the median household income fell by more than $900. Ezra Klein, "Stock Split"
Argument; conclusion: To focus on the performance ... the country does poorly.
Scientists have recently shown that heaps of intact DNA from the extinct wooly mammoth are retrievable from the animals' fur. A great deal of that fur is readily available in natural history museums. Such amounts of DNA make it possible to piece together the entire mammoth genome. Hence, we can expect to see mammoth clones in the not too distant future.
Argument; conclusion: We can expect to see ... in the not too distant future.
Which of the following are all inductive arguments?
Arguments from authority, arguments from analogy, causal inferences.
After smoking only a few cigarettes per day, Krista became addicted within two months. The same thing happened to Dave, Jean, and Marty. Therefore, since Dennis has been smoking a few cigarettes per day for the past two months, he's probably addicted, too.
Inductive, strong.
Which of the following are all nonarguments?
Conditional statements, explanations, statements of belief.
Given that figure A is a triangle, and one of its sides has a length of 1 foot. It follows that its area is less than 1 square foot.
Deductive, invalid
Andrew is lighter than Carl, and Carl is heavier than Marty. Therefore, it follows necessarily that Andrew is lighter than Marty.
Deductive, invalid.
Given that A and B are the diagonals of a parallelogram. It follows that A and B have the same length.
Deductive, invalid.
If football is a rough sport, then football injuries abound. It is the case that football injuries abound. Thus, it follows that football is a rough sport.
Deductive, invalid.
If organic food contains pesticides, then consumers are misled. Organic food does not contain pesticides. Therefore, consumers are not misled.
Deductive, invalid.
If the Big Bang theory is correct, then the universe is billions of years old. And if the Big Bang theory is correct, then the universe was not created in six days. Thus, if the universe is billions of years old, then it was not created in six days.
Deductive, invalid.
Lydia loves Ryan, and Ryan loves anchovy pizza. Therefore, it follows necessarily that Lydia loves anchovy pizza.
Deductive, invalid.
No drug cartels are legal operations, so no legal operations are enterprises that engage in smuggling, because all drug cartels are enterprises that engage in smuggling.
Deductive, invalid.
Some preachers are evangelists, so some preachers are TV personalities, since some evangelists are TV personalities
Deductive, invalid.
All aerobic exercises are calorie burners and all calorie burners are weight reducers. Thus, all aerobic exercises are weight reducers.
Deductive, valid.
Brandon is a polytheist. Therefore, he believes in more than one god.
Deductive, valid.
Either Bill Clinton or George W. Bush was president when the World Trade Center towers were destroyed. But Bush was not president at that time. Therefore, Bill Clinton was president when those buildings were destroyed.
Deductive, valid.
Either Jennifer Lawrence or Elon Musk is a popular film star. But Jennifer Lawrence is not a film star at all. Therefore, Elon Musk is a popular film star.
Deductive, valid.
Given that x2 + 2x = 15. It follows that x = 3.
Deductive, valid.
If Ken Burns makes historical documentaries, then he enhances our knowledge of the past. Ken Burns does make historical documentaries. Therefore he enhances our knowledge of the past.
Deductive, valid.
Natalie is a kleptomaniac. Therefore, she has a compulsion to steal things.
Deductive, valid.
Which of the following is a necessary condition for graduating from college?
Fulfilling the course requirements.
Which of the following is a sufficient condition for winning an election?
Getting more than half the votes.
Which of the following is a necessary condition for playing baseball?
Having a bat.
Which of the following are all conclusion indicators?
Hence, thus, so.
Which of the following are all deductive arguments?
Hypothetical syllogisms, disjunctive syllogisms, arguments based on mathematics.
After buying a pair of Blue Atlas jeans, Carter was disappointed to find that they fell apart after only one month. The same thing happened to Jeff, Mario, and Ralph. Apparently, Blue Atlas jeans don't hold up very well.
Inductive, strong.
After drinking a bottle of Black Diamond Special Brew, Clyde noticed a slightly bitter aftertaste. Lauren and Nicole noticed the same thing when they drank some Black Diamond a year earlier. We conclude that every bottle of Black Diamond Special Brew has a slightly bitter after taste.
Inductive, strong.
After examining DNA evidence found at the crime scene, Dr. Jacobs, a highly qualified forensic biologist, says that Alex Foster could not have committed the crime. Therefore, we conclude that Foster is innocent.
Inductive, strong.
After hearing Jordan's speech in the student council, Michael rolled his eyes and shook his head. Apparently Michael didn't agree with what Jordan said.
Inductive, strong.
An element is a collection of atoms of the same type. Each atom contains three fundamental particles—aproton, a neutron, and an electron. The protons and neutrons are in the center, or nucleus, of the atom. Protons have a positive charge, while neutrons have no electric charge. The electrons have a negative charge and orbit about the nucleus at a specific distance. Edward F. Albin, Earth Science Made Easy
Nonargument
Aristotle focused on clarifying the concept of virtue itself. He argued that it was virtuous to choose the proper amount of emotion and/or action called for in a particular situation and that extremes of emotion and action were vices. In all communities there are some men of practical wisdom who have the capacity to judge wisely. Aristotle argued that they have the capacity to follow the "right rule" whatever the situation. David Cooper, Value Pluralism and Ethical Choice
Nonargument.
Authoritarian states are characterized by strong central governments that fairly stringently limit the range of political activity. More often than not, they are one-party states, which means that only one party, that which supports the government, is allowed to engage in political activity. Free discussion and association are strictly curtailed in these systems. Anyone who might dare to criticize the government or to express ideas that are not in conformity with its policies can be severely punished, even by death. Robert A. Heineman, Political Science
Nonargument.
Evolution as a process that has always gone on in the history of the earth can be doubted only by those who are ignorant of the evidence or are resistant to evidence, owing to emotional blocks or to plain bigotry. By contrast, the mechanisms that bring evolution about certainly need study and clarification. There are no alternatives to evolution as history that can withstand critical examination. Yet we are constantly learning new and important facts about evolutionary mechanisms. Theodosius Dobzhansky, Nothing in Biology Makes Sense Except in the Light of Evolution
Nonargument.
Geology can be divided into two major time-related disciplines: physical geology and historical geology. Physical geology is the study of the materials the planet is composed of and the present day processes that operate on the surface and within the earth's deeper layers. Historical geology is the study of the earth's 4.6 billion year history, its formation, development, and evolution. Historical geologists strive to create a time-line of events that have occurred since the earth's formation. Alan D. Sills, Earth Science the Easy Way
Nonargument.
Hair turns color when we age because the follicles at the base of the hair shaft cease to produce melanin. Melanin is a chemical that gives the hair shaft its color (black, brown, blond, red, and all shades in between). The darkness or lightness of your hair depends on how much melanin each strand contains. With age, the cells in the follicle that produce melanin die off. As they do so, that hair strand will become silver, grey, or white, as it grows.
Nonargument.
Harnessing the clean, abundant energy of the sun and wind is critical to solving the global warming problem. Technological advances have brought the cost of electricity generated by the wind down by 82 percent since 1981. Solar energy technology has made remarkable progress as new photovoltaic cells have been developed to convert even greater amounts of sunlight directly into electricity. Today the costs of wind and solar power are becoming competitive with dirty coal-fired plants. Sierra Club, "Global Warming Solutions"
Nonargument.
If its ion engine operates as planned, its huge solar panel remains deployed and undamaged, and its xenon energy source is not exhausted, then the Dawn spacecraft will reach both Vesta and Ceres (large asteroids in the belt between Mars and Jupiter), and scientists will gather information about the formation of planets, whether Ceres has a buried ocean of fresh water, and whether vestiges of life lurk beneath its icy surface.
Nonargument.
If the trade in tiger products is banned, tiger reserves are guarded by well equipped staff, communities abutting tiger habitat are given a stake in protecting tigers, and the makers of traditional medicines can be persuaded that tiger parts are not needed, then tiger poaching will be halted, habitat and life sustaining prey will be restored, and the immanent extinction of tigers in the wild will be averted.
Nonargument.
Lead is toxic, but do you know why? Lead is toxic mainly because it preferentially replaces other metals in biochemical reactions. In so doing it interferes with the proteins that regulate blood pressure (which can cause development delays in children and high blood pressure in adults), heme production (which can lead to anemia), and sperm production. Lead also displaces calcium in the reactions that transmit electrical impulses in the brain, which diminishes the ability to think and recall information. Anne Marie Helmenstine, "Your Guide to Chemistry"
Nonargument.
Little is known of the Greek physician Hippocrates, who lived around 400 B.C. Nevertheless, the writings attributed to him have provided a number of principles underlying modern medical practice. One of his most famous contributions, the Hippocratic Oath, is the foundation of contemporary medical ethics. It requires the physician to swear that he or she will help the sick, refrain from intentional wrongdoing, and keep confidential all matters pertaining to the doctor-patient relationship. William C. Cockerham, Medical Sociology
Nonargument.
Nicotine is addictive because its chemical structure is so similar to the neurotransmitter acetylcholine that once inside the brain it unlocks several other chemicals. One of these chemicals is dopamine, which produces a highly pleasant sensation. Another is adrenaline, which increases alertness. Yet a third is serotonin, which improves one's mood. When people are deprived of these chemicals, they naturally want more, and this leads to addiction.
Nonargument.
Numerous studies have indicated that women of color, black women in particular, are over-arrested, over-indicted, and over-sentenced. African-American women are seven times more likely to be arrested for prostitution than women of other ethnic groups. Black women have received significantly longer sentences for crimes against property and served longer periods in prison. For both murder and drug offenses, Euroamerican women ended up serving one-third less time for the same offenses than black women. Nancy Kurshan, "Women and Imprisonment in the U.S."
Nonargument.
The earth is divided into the crust, the mantle, and the core. The crust is the solid portion on which we stand. The mantle is a plastic but solid material under the crust that can flow and move about. And finally, the core is the innermost part of the earth made of solid and molten iron. Pam Walker and Elaine Wood, Hands-On General Science Activities
Nonargument.
The relationship between two measurable factors can be represented by a graph. If both values increase, they are considered to have a direct relationship. For example, the more you work, the more money you make. If one value increases while the other decreases, they have an inverse relationship. For example, the more you work on your golf swing, the lower your score will be. Scott Ryan, Earth Science
Nonargument.
Two million children have been killed in armed conflicts in the last decade. Three times as many have been injured or permanently disabled. Millions of others have been forced to take part in or witness horrifying acts of violence. In countless cases the impact of armed conflict on children's lives remains invisible. The children themselves may be removed from the public, in institutions, or survive as victims of prostitution. But those who have lost parents often experience humiliation, rejection and discrimination, and suffer in silence as their self-esteem crumbles. Child Rights Information Network
Nonargument.
Viruses are acellular entities too small to be seen with a light microscope. They are composed of a nucleic acid and a few proteins. Viruses replicate themselves and display other properties of living organisms only when they have invaded living cells. Indeed, some viruses can be crystallized and stored in a container on a shelf for years, but they retain the capacity to invade cells and cause disease. Jacquelyn C. Black, Microbiology: Principles and Explorations
Nonargument.
While there is no technology to reduce CO2 from a car's exhaust, we can make cars pollute less by making them more fuel efficient. By using today's best technology, car makers could dramatically increase the fuel economy of their cars and trucks. In fact, off-the-shelf technology can change the nation's best selling SUV, the Ford Explorer, from a 19 mpg gas guzzler to an efficient 34 mpg vehicle. If we are to make any progress in slowing global warming, we must make our cars go farther on a gallon of gas. Sierra Club, "Global Warming Solutions"
Nonargument.
If a deductive argument has all false premises and a true conclusion, then we know:
Nothing as such about the argument's validity.
If a deductive argument has one true premise and a true conclusion, then we know:
Nothing as such about the argument's validity.
Which of the following are all arguments?
Predictions, categorical syllogisms, arguments from signs.
Which of the following is a sufficient condition for committing a crime?
Robbing a bank.
Which of the following are all premise indicators?
Since, given that, because.
Words like 'due to the fact that' and 'assuming that' suggest that whatever follows is
a premise
As understood by logicians, an argument is
a set of statements, one of which is intended to be supported by the others.
A premise of an argument is always
a statement intended to provide support for the conclusion
The premises of an argument
a statement intended to provide support for the conclusion
A conclusion of an argument is always
a statement which is supposed to be supported by the other statements in the argument
Words like 'as a result' and 'therefore' tend to indicate
conclusions
Words like 'it follows that' and 'consequently' tend to indicate
conclusions