The Art of Argument:Exploring Toulmin Logic

By Patrick, Daniel and Rodney

Stephen Toulmin

• British philosopher, author, and educator• Devoted his works to the analysis of moral

reasoning• Believed absolutism has limited practical value• Introduced practical argument method

New System of Logic

• Based on justification rather than inference• More literal rather than theoretical• New argument could now stand up to criticism• Published in his book “The Uses of

Argumentation”

ClaimData

Warrant

Data: information that is gathered through observation or experimentationWarrant: inferences or assumed beliefs that support the claim, can be based upon logos, pathos, ethos, or shared valuesClaim: the statement that one is asserting

Definitions

Structure of Logic

• Using data, supported by a warrant, to form a claim.• Warrant supports data which supports claim.• Backing, qualifiers and rebuttals can further support

the claim• Very literal and scientific approach

ClaimData

Warrant

Simple Example

• Data: My pen is not writing on the paper• Claim: My pen has run out of ink• Warrant: Pens without ink do not write

Data

Warrant

Claim

One Step Further

• Backing: a credible source or citation, backing up the warrant

• Qualifier: Indicates speaker’s degree of certainty of the claim, often uses words such as certainly, absolutely, maybe, etc.

• Rebuttal: argument opposing the opposition, can be in the same setup (i.e. data, claim, warrant),

Full Structure of Toulmin Logic

ClaimData

WarrantRebuttal

Qualifier

Backing

Simple Example Expanded

• Data: My pen is not writing on the paper• Claim: My pen has run out of ink• Warrant: Pens without ink do not write• Backing: Bic came out with a study proving that pens

with less than 5% of the original supply of ink cannot write properly

• Qualifier: I am completely sure this pen ran out of ink• Rebuttal: There are other problems that can lead to

the malfunction of pens, such as a broken tip

Advantages to using Toulmin Logic

• Presents argument structure that facilitates support and validity for said argument.

• Always room for doubt in an argument, leaving room for reasons yet undiscovered and rebuttal

• Allows for logic to be updated as new discoveries are made

• Arguments can be presented and debated as long as you have some data to back up your claim

• Presents arguments literally rather than theoretically (dichotomy)

Disadvantages to using Toulmin Logic

• Does not allow for absolutes• Requires an extensive support system if the

claim is to be validated• Can always be disputed as there is always a

limited degree of validity

Uses in School

• Science Labs• Socratic Seminars• Persuasive Essays• Debates

Uses in the Real World

• Lawyers• Scientists• Statistics• Will• Politicians• Literary Analysts• Everyday life

Real Life ExampleEach year, a World Championship Pumpkin Weights

Competition is held to determine the largest pumpkin of the year. Here are the data for years 1979 to 2007

Year Weight (lb) Year Weight (lb) Year Weight (lb)1979 438.5 1989 755 1999 11311980 459 1990 816.5 2000 11401981 493.5 1991 780.5 2001 12621982 445 1992 827 2002 1337.61983 481 1993 884 2003 13851984 612 1994 990 2004 14461985 531 1995 968 2005 14691986 671 1996 1061 2006 15021987 604.5 1997 977 2007 16891988 633 1998 1092

Analysis• Claim: as years increase, farmers will grow larger

and larger pumpkins because of genetic modification biology

• Warrant: Pumpkins modified to grow larger will grow larger

• Backing: Genetic modification of potato development using Ri T-DNA scholarly article by G. Ooms, A. Karp, M. M. Burrell, D. Twell and J. Roberts proved that potatoes and other vegetables/fruits can be genetically modified to grow larger

• Qualifier: These data were recorded in the World Championship which is a valid event

• Rebuttal: N/A

The EndClaim

Data

Warrant

Backing

Data

Warrant

Qualifiers

Rebuttal

Qualifiers

QualifiersQualifiers

QualifiersQualifiers

Data

Warrant

Backing Backing(Daniel’s Original Model of Toulmin Logic)