Presentation on theme: "Inductive vs. Deductive Reasoning Descriptions and examples."— Presentation transcript:
Inductive vs. Deductive Reasoning Descriptions and examples
Types of Reasoning Deductive reasoning goes from general to specific Inductive reasoning goes from specific to general
Deductive Reasoning Deductive reasoning starts with a premise, which we accept to be true. Then, from that rule, we make a conclusion about something specific. Example: All turtles have shells The animal I have captured is a turtle I conclude that the animal in my bag has a shell
Deductive Reasoning A conclusion reached with deductive reasoning is logically sound, and airtight, assuming the premise is true. If a penny is a flat disc, copper in color and has a profile of Honest Abe on it, then I can be sure the penny in my pocket has those qualities.
Deductive Reasoning The strength of deductive reasoning is that conclusions derived with it are fully certain. The weakness, which was illustrated in the most recent example, is that no new information is added. The fact that the penny in my pocket is a copper disc with Lincoln on it was clear from the initial data, so the conclusion hasn't added any new information.
Inductive Reasoning Inductive reasoning is making a conclusion based on a set of experiences or data. If I observe that something is true many times, concluding that it will be true in all instances is a use of inductive reasoning. Example: All sheep that I've seen are white All sheep must be white
Inductive Reasoning The strength of inductive reasoning is that new information came be stated. The weakness is that the new information cannot be proven.
Deductive Reasoning All dogs are mammals and mammals have kidneys. Therefore your dog has kidneys.
Deductive Reasoning All squares are rectangles, and all rectangles have four sides. All squares have four sides.
Deductive Reasoning All chemists are smart if chemists are scientists and all scientists are smart.
Inductive Reasoning All swans we have seen have been white; therefore all swans are white.
Inductive Reasoning All swans we have seen have been white; therefore the next swan we see will be white.
Inductive Reasoning All known planets travel about the sun in ellipitical orbits; therefore all planets travel about the sun in ellipitical orbits.
Deductive or Inductive? Since all men are mortal, and Socrates is a man, Socrates is mortal.
Deductive or Inductive? Exploration of the surface of Mars has produced some surprising facts. Therefore exploration of the surface of Jupiter will produce some surprising facts.
Deductive or Inductive? Since Chris is a good athlete, Chris's sister must be a good athlete also.
Deductive or Inductive? The sun is a star; the sun has planets; therefore some stars have planets.