Developed by British philosopher Stephen
Toulmin in the 1950’s
Emphasizes that logic often based on
probability rather than certainty
Focuses on claims
Informal logic: based on probability. Gives
good reasons, persuasive arguments. Does
not attempt to prove….
Acknowledges reasonable arguments of
Enthymeme gives the three primary
Claim = statement of the main point or
Data = the evidence supporting the claim,
aka the reasons
Warrant = an underlying/unstated
assumption or basic principle that connects
data and claim; as said before, perhaps
implied rather than explicit
Grounds: provide actual evidence in
support of the reasons.
◦ Examples, statistics, citations, facts
Backing: supports warrant, if needed.
Conditions of Rebuttal: bring up and
address counter-arguments. Attacks
grounds and/or the warrant and backing.
Qualifier: limits a claim. Gets rid of
absolutes. Can prove a claim is faulty if
given absolutes like always, never…..can
find exceptions to such broad statements.
Claim = My parents should allow me to go to my
friend’s party on Friday night.
Data = The parents of nearly all of the seniors at
CHS have given their children permission to
attend this party.
Warrant = My parents should act in accordance
with the other parents of juniors at CHS.
What if my parents don’t “buy” my warrant?
What if they don’t think they should
necessarily do what other parents are doing?
How can I still get permission to attend the
party? Or at least have a better chance of
What might be more convincing data for an
audience of parents?
What might be a warrant that most parents