, Deductive vs. Inductive Reasoning
Deductive reasoning Facts
Essential details to make a reasoned decision present
Inductive reasoning Less structured
Conclusion may not follow on from the premises
Do not directly consider validity as in deductive argument
Instead look at STRENGTH of argument:
- STRONG argument – decide that conclusion = true
- WEAK argument – decide that the conclusion = not true
Inductive argument gives us the basis to say whether the
conclusion is probably true vs definitely true
Number of factors Contribute to perceived strength of an
inductive argument:
- Representativeness of Observations: how well do your
observations match with previous ones
- Number of Observations: More observations strengthen a
conclusion
Fewer observations = weaker the conclusion
- Quality of Evidence: Sound obvious, but the stronger the
evidence – stronger the argument – stronger the conclusion
Inductive reasoning in Everyday Life
Use inductive reasoning to guide us through any number of
conclusions that refer to past experiences or events
Consider these two examples:
On a module that you are taking with Dr. X you observe that
he/she
asks a lot of questions about experimental methods in the
final exam
- Based on this observation, would conclude that exams for
other of Dr. X’s courses would be very similar in content
You buy something from a mail order company & get good
service –
you therefore place another order with the same company
based on an
observation of previous good service
Make any number of predictions about what will happen
based on what
has happened previously
Great deal of common sense surrounding the specifics of
inductive reasoning
Make choices & predictions based on our past experiences &
events
2
Deductive reasoning Facts
Essential details to make a reasoned decision present
Inductive reasoning Less structured
Conclusion may not follow on from the premises
Do not directly consider validity as in deductive argument
Instead look at STRENGTH of argument:
- STRONG argument – decide that conclusion = true
- WEAK argument – decide that the conclusion = not true
Inductive argument gives us the basis to say whether the
conclusion is probably true vs definitely true
Number of factors Contribute to perceived strength of an
inductive argument:
- Representativeness of Observations: how well do your
observations match with previous ones
- Number of Observations: More observations strengthen a
conclusion
Fewer observations = weaker the conclusion
- Quality of Evidence: Sound obvious, but the stronger the
evidence – stronger the argument – stronger the conclusion
Inductive reasoning in Everyday Life
Use inductive reasoning to guide us through any number of
conclusions that refer to past experiences or events
Consider these two examples:
On a module that you are taking with Dr. X you observe that
he/she
asks a lot of questions about experimental methods in the
final exam
- Based on this observation, would conclude that exams for
other of Dr. X’s courses would be very similar in content
You buy something from a mail order company & get good
service –
you therefore place another order with the same company
based on an
observation of previous good service
Make any number of predictions about what will happen
based on what
has happened previously
Great deal of common sense surrounding the specifics of
inductive reasoning
Make choices & predictions based on our past experiences &
events
2
