Basic Concepts Flashcards
An argument is factually correct if and only if…
all of the premises are true
An argument is sound if and only if…
it is both factually correct and valid.
An argument is valid if and only if…
the conclusion follows from the premises.
What are conclusion markers?
Words or phrases that might indicate the presence of a conclusion.
“Therefore” “hence” “thus” “in conclusion”
A lack of conclusion markers does not mean a lack of conclusion.
The presence of conclusion markers does not necessarily mean a conclusion is present.
What is the counter-example method?
A way of proving the invalidity of an argument by showing an invalid counter-example of the same form.
If an argument admits a counter-example of the same form, with true premises and a false conclusion, the original argument is invalid.
What is the difference between imply and infer?
Not to be confused.
- Something is implied when presented information suggests but does not directly state that something
- Something is inferred when a reasoning entity deduces that something based on presented information
Premise Markers
Words or phrases that suggest the presence of a premise.
“since” “for” “because”
Not all premises will use recognizable markers so it is important to be able to identify a premise by reasoning.
Conversely, the presence of a marker does not necessarily indicate the presence of a premise.
What is the Principle of Counter-examples?
- An argument (form) is invalid if it admits a counter-example.
- An argument (form) is valid as long as it admits no counter-examples
By demonstrating that an argument admits a counterexample of the same form with a false conclusion, you demonstrate that the argument form is invalid as it is a substitution instance of that form.
Probably but fallible is a quality of…
a conclusion found in inductive reasoning.
While the premises of an inductive argument make the conclusion more likely (probable), there is still room for error (fallible).
The form of a statement is a function of…
the arrangement of its terms.
The form of an argument is a function of…
the form of the individual statements that comprise it.
True or False: A factually correct argument is always valid.
False: Any argument with all true premises can have a false conclusion. Any argument with all true premises and a false conclusion is invalid.
True or False: a lack of counter-examples proves an arguments validity.
False: While no counter-examples might make an arguments validity more likely, it may simply be the case that a counter-example has yet to be found.
True or False: a proposition can have multiple statements.
True: A statement can be formulated in multiple ways or languages to communicate a proposition.
- The snow is white.
- Der schnee ist weiss.
- La neige est blanche.
True or False: a single statement has only one proposition.
False: A single statement can have multiple propositions depending on context and speaker.
“I am hungry” has different propositions when spoken by different people.
It can also imply something other than a physical need for food. “I am hungry (for action)”
True or False: A valid argument can be made from the argument form derived from an invalid argument.
False
True or False: A valid argument has all true premises.
False: An argument is valid if the truth of its conclusion is necessitated by the truth of its premises. That is to say that an argument with false premises can still be valid if the arguments conclusion follows if the premises were true.
True or False: Any argument with the same form as a valid argument is also valid.
True
Valid or Invalid: An argument with all true premises and a false conclusion.
Invalid
Valid or Invalid: An argument with all true premises and a true conclusion.
Undetermined. More information needed.
Valid or Invalid: An argument with not all true premises and a false conclusion.
Undetermined. More information needed.
Valid or Invalid: An argument with not all true premises and a true conclusion.
Undetermined. More information needed.