Key This practice test has the same format as the test on Wednesday 10/2/2013. Obviously, I cannot give credit to students who submit this exercise now that I have posted this key.
Phil 170 Extra Credit Test #1 Name___________________________
Answer "true" or "false" to the following statements. (12pts)
and continue to refine and utilize the habits and infrastructure necessary to remain informed and
effective thinkers. True
Answer with complete, grammatical sentences. (2pts)
13.) What is the difference between inductive and deductive inferences?
In general inferences are psychological processes that transform information available and explicit, i.e., usable information, to a person (or to some cognitive process of that person) to generate new available and explicit information. Deductive and inductive inferences differ in tradeoffs made between tractability, speed, power, and truth underlying their respective processes. On the one hand, deductive inferences work to preserve the truth of one’s initial information by generating only truths when operating on truths. Thus, deductive inferences only reveal what must be true given the truth of one’s initial information. Good deductive inferences (valid deductive inferences) operate such that if the initial information is true, the inferential transformation necessarily generates true information. On the other hand, inductive inference extends one’s stock of truths beyond those truths necessitated by what the reasoner already knows. Inductive inferences amplify a reasoner’s knowledge by implicitly or explicitly assuming various regularities regarding the structure of the world or regularities in the way the world changes. Inductive inferences, by making such assumptions, introduce a degree of risk into one’s inferences in order to extend one’s stock of truths.
Extract the following arguments from the text, putting them in standard form and providing any missing premises. (12pts)
14.) The person most likely to kill you is yourself: In 2004 32,439 people killed themselves in the United States while 17,357 homicides occurred that year. The 2004 numbers are typical annual ratios.
In 2004 17,357 people were killed by other people (i.e., homicides).
In 2004 32,439 people killed themselves in the United States (i.e., suicides).
This ratio of nearly twice as many suicides as homicides in 2004 is a typical annual ratio.
Thus, the person most likely to kill you is yourself.
15.) It seems likely only that the richest Americans have profited from the economic growth in the U.S. from 1970 to 2000. In his book, Perfectly, Legal, David Clay Johnston–the Pultizer prize-winning financial journalist cites a study by economists Thomas Piketty and Emmanuel Saez showing that the average income of the bottom 90% of U.S. citizens fell .1% between 1970 and 2000. In contrast, the average income of the top 13,360 wealthiest people in the U.S. rose 412%.
The average income of the bottom 90% of U.S. citizens fell .1% between 1970 and 2000.
In contrast, the study also shows that average income of the top 13,360 wealthiest people in the U.S. rose 412%.
These figures come from a study by economists Thomas Piketty and Emmanuel Saez cited by Pultizer prize-winning financial journalist David Clay Johnston.
The figures indicate that between 1970 and 2000 90% of Americans saw no real increase in their average income while the top 1% saw a dramatic increase in their average income.
Thus, it seems likely only that the richest Americans have profited from the economic growth in the U.S. from 1970 to 2000.
For each of the following passages determine whether they contain arguments. If they contain arguments, then determine if those are inductive or deductive, valid or invalid, weak or strong. (6pts)
16.)People who have never been married are seven and a half times more likely than married people to be admitted to a psychiatric facility. Thus, we should expect an increase in mental illness, since fewer people are getting married now days.
This is an example of an inductive argument. It infers that an inverse correlation between marriage and mental illness (i.e., married people are less likely to develop mental illness), will remain constant so that increased numbers of single people will also result in increased numbers of people who develop mental illness. The argument is a weak inductive argument because it provides no evidence that marital status and decreased incidence of mental illness are linked. The observed correlation may nor may not be causally connected as opposed to accidentally connected.
17.)Recapitulation theory, famously formulated by E.H. Haeckel in 1874, asserts that the embryonic development of all living creatures passes through stages similar in general structural plan to the stages their species passed through their evolution; more technically phrased, the theory that ontogeny is an abbreviated recapitulation of phylogeny. Because of the connection between development and evolution in Haeckel’s theory, it has been thought to provide evidence for evolution. However, Haeckel is known to have falsified his drawings in support of the theory. Thus, evolution is probably a false theory.
This too is an inductive argument. It infers the improbability of evolution theory from the falsity of a theory once thought to support evolution. The argument is also weak. Evolution is not rendered improbable if one theory once thought to support it proves false. Evolution is one of the best evinced theories in science.
For the following invalid argument, make the form explicit and create a substitution instance (counter example) that shows the argument invalid. (8pts)
18.) Some fish are phyllodes. Some phyllodes are trout. So, some fish are trout.
This is a categorical argument.
Logical Form Substitution Instance
Some F are P. Some dogs are mammals. True F = dogs
Some P are T. Some mammals are cats. True P = mammals