The Structure of Arguments
o Deductive: conclusion follows necessarily from premises (reasons)
Very powerful argument (like math)
You can be wrong here, but if first part is right, second part must be right
If premises are true, the conclusion must be true
Valid: specific, logical operate (nothing to do with truth); conclusion must follow
Invalid: fails to give conclusive support
Sound: valid arguments, truth
Unsound: invalid, with at least one false premise
All men are mortal. Socrates is a man. Therefore, Socrates is mortal. } Follows
premise Valid, in this case, it is sound
All bachelorettes are female. Jen is a bachelorette. Therefore, all females are
Jen. } Conclusion doesn’t make sense Invalid and unsound
o Inductive: conclusion supported by premises to some degree
All sciences, physics
My pit bull is vicious; so all pit bulls are vicious.
A lot of room for error.
If the premise is true, conclusion more likely to be true (but could be false). Could be exception, we don’t know
All swans are white. (Not always true)
We could look at 1000 swans to determine if all swans are white.
Personally, I have only seen white swans but if we see a black swan Most
swans are white. (Less strong/convincing)
Probable support to conclusion
A lot of argumentation in science, no certainty
Not meant to give decisive support
85% of Twilight fans prefer Edward to Jacob. Sarah is a Twilight fan. Therefore,
Sarah probably prefers Edward to Jacob. (Specific General)
o Reason + Reason = Conclusion
o Strong argument: probable support
o Weak argument: little to no support
o We cannot say it is invalid or false.
A form of thinking in which certain statements are offered in support of another statement
Reasons (Premise) Cue words:
o Since, in view of, for, because, furthermore, as shown by, given that, after all, for the
reason that, may be inferred/derived from, first of all, as indicated by, assuming that,
Conclusions Cue words:
o Therefore, hence, allows us to infer, you see/agree that, then, thereby showing, points
to, thus, consequently, as a result, implies that, leads me to believe, so
o I think. Therefore, I exist. o Since (premise) … I won’t (conclusion) …
o You … so that’s why (conclusion) …
o How true are the reasons?
o To what extent, do the reasons support conclusions?
o Does the argument pass test of truth and validity?
What an argument is not: