Chapter 5 pp 222 225 pp 234 236 Inductive Reasoning An inductive argument is like a puzzle with some pieces missing o There will always be an element of doubt in this argument Conclusion can only be said to follow with likelihood or probability never with The conclusion goes beyond what is contained in the premises We have to be careful what applications we make of an inductive argument Ex 1 Beyonce is the Joan Baez of this century She has a voice that travels well just like Joan Baez who could bounce her voice off She is a striking physical presence just like Joan Baez who had big eyes fine bones certainty a mountain and beautiful lone hair at the peak of her beauty She has a host of imitators just like Joan Baez So I bet Beyonce is against war too Joan Baez was also an outspoken pacifist What we have here is a list of similarities between the two signers voice looks and imitators The inference is then drawn that they must also have similar political views Even if terms of comparison were all true it is unclear if the additional trait holds as well political views Major Kinds of Inductive Arguments 1 Predictions an argument is made about the future based on past or present evidence follow 2 Arguments about the past based on present evidence an inference is drawn about what happened at some earlier point in time based on current evidence 3 Cause and effect Relationship it is claimed that an event is based on one or more causal factors Given the instance existence then of the causal factor s the effect should 4 Arguments based on analogy rests on a comparison from which it is claimed that a characteristic true of the one term in the equation will also be true of the other In law this usually involves the application of a precedent or legal principle 5 Statistical Reasoning draw from sample studies or statistical reasoning from which an inference then is drawn about either all or part of the targeted population Shifting Gears in Statistical Reasoning Whenever we go form a sample study or a poll to a larger population as in statistical reasoning we have shifted gears and made a move not seen in deductive reasoning Deductive Argument Example o 43 of residents of Ann Arbor said they prefer rice to potatoes o Everyone who prefers rice to potatoes consumes more soy sauce than ketchup o Therefore 43 of residents of Ann Arbor consume more soy sauce than Ketchup Inductive Argument Example o o o 76 of residents of Brush Prairie hike three to four times a week Brush Prairie is a town in Washington state Therefore 76 of residents of Washington State hike three to four times a week The Wedge of Doubt in Inductive Arguments The premises could be true but the conclusion will never follow with certainty There is always some wedge of doubt between the premises and the conclusion We can construct inductive arguments following one of the different forms of inductive reasoning Ex 1 An analogy Lance Armstrong is like a hummingbird He pedals 100 110 rpm while his rivals tend to slow to about 70 rpm Therefore Armstrong will be bale to use cardiovascular strength instead of relying on muscle power Ex 2 A Prediction According to the poll taken at Universal City Senior Center the movie the Visitor will win Best Picture for 2008 Readers polls are pretty darn accurate most of the time Therefore The Visitor will almost certainly win Best Picture 2008 Ex 3 Statistical Reasoning Only 6 of people in the Gallup Poll on June 7 2008 said they were unsure who to vote for president Vashti was one of the people who was polled Therefore Vashti is probably sure who she ll vote for president Assessing Inductive Arguments Are assessed in terms of strength not validity