The **_Argument Model Ontology (AMO)_** is an OWL 2 DL ontology that aims to encode the [Toulmin's theory](https://doi.org/10.1017/CBO9780511840005) through OWL classes and properties, in order to describe a web of inter-linked entities that participate, with a specific role, in one or more arguments.
Toulmin's model of argument focuses on the justificatory function of argumentation: rather than evaluating arguments through formal logic, it describes how people, in practice, put forward a claim and then justify it.
According to this model, every practical argument can be analysed in terms of six interrelated components.
Three of them are essential: the claim to be established, the evidence (or data) on which it is founded, and the warrant that bridges from the evidence to the claim.
The other three may be omitted in some arguments: the backing that certifies the warrant, the qualifier that expresses the degree of certainty of the claim, and the rebuttal that states the conditions under which the claim would not hold.
AMO models an argument through the class `amo:Argument`, whose components are instances of `amo:Claim`, `amo:Evidence`, `amo:Warrant`, `amo:Backing` and `amo:Rebuttal`, all grouped under the class `amo:ArgumentationEntity`, and of `amo:Qualifier`.
An argument is linked to its components through the sub-properties of `amo:involves` (i.e., `amo:hasClaim`, `amo:hasEvidence`, `amo:hasWarrant`, `amo:hasBacking`, `amo:hasQualifier` and `amo:hasRebuttal`), and each argument must have exactly one claim and at least one evidence and one warrant.
The components are, in turn, linked to one another: an evidence proves a claim (`amo:proves`) and supports a warrant (`amo:supports`), a warrant leads to a claim (`amo:leadsTo`), a backing backs a warrant (`amo:backs`), a qualifier forces a claim (`amo:forces`), and a claim is valid unless a rebuttal holds (`amo:isValidUnless`).
Several of these relations are automatically inferred, by means of property chains, from the description of the roles that the components hold within the argument.
AMO is aligned with the [Citation Typing Ontology (CiTO)](http://purl.org/spar/cito), an ontology for the characterization of citations, both factually and rhetorically that forms part of [SPAR, a suite of Semantic Publishing and Referencing Ontologies](http://sparontologies.net).
## Examples of use
In the following subsections, we introduce some examples to showcase how to use AMO.
The prefixes that are used in all the examples provided below are defined as follows:
@prefix amo: <http://purl.org/spar/amo/> .
@prefix : <http://example.org/> .
### Describing the components of an argument
Consider the argument "This ontology was developed in OWL, and since an ontology developed in OWL is a consistent OWL ontology, as stated by the OWL 2 specifications, this is presumably a consistent OWL ontology, unless a reasoner for OWL 2 proves that it is not consistent".
The argument can be described from a high-level perspective by stating which argumentation entities it involves and which role each of them holds.
:argument a amo:Argument ;
amo:hasClaim :consistency-claim ;
amo:hasEvidence :developed-in-owl ;
amo:hasWarrant :owl-warrant ;
amo:hasBacking :owl2-spec ;
amo:hasQualifier :presumably ;
amo:hasRebuttal :reasoner-rebuttal .
:consistency-claim a amo:Claim .
:developed-in-owl a amo:Evidence .
:owl-warrant a amo:Warrant .
:owl2-spec a amo:Backing .
:presumably a amo:Qualifier .
:reasoner-rebuttal a amo:Rebuttal .
### Describing the relations between argumentation entities
The same argument can be described from a factual perspective, by stating how its argumentation entities are linked to one another.
The relations between evidence and claim, warrant and claim, qualifier and claim, and claim and rebuttal can also be inferred from the high-level description through the property chains defined in AMO.
:developed-in-owl amo:proves :consistency-claim ;
amo:supports :owl-warrant .
:owl-warrant amo:leadsTo :consistency-claim .
:owl2-spec amo:backs :owl-warrant .
:presumably amo:forces :consistency-claim .
:consistency-claim amo:isValidUnless :reasoner-rebuttal .
## Competency Questions
AMO can be used for answering several questions related to arguments and how argumentation entities are related to each other.
In the following subsections, some of them are introduced together with their respective SPARQL queries.
The prefixes that are used in all the SPARQL queries provided below are defined as follows:
PREFIX amo: <http://purl.org/spar/amo/>
PREFIX : <http://example.org/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
### CQ1
What is the claim of a given argument, and which evidence proves it?
SELECT ?claim ?evidence
WHERE {
:argument amo:hasClaim ?claim ;
amo:hasEvidence ?evidence .
}
### CQ2
Which warrants lead to a given claim, and which backings attest them?
SELECT ?warrant ?backing
WHERE {
?warrant amo:leadsTo :consistency-claim .
OPTIONAL { ?backing amo:backs ?warrant }
}
### CQ3
What is the degree of force of a given claim, and under which rebuttals is it not valid?
SELECT ?qualifier ?rebuttal
WHERE {
OPTIONAL { ?qualifier amo:forces :consistency-claim }
OPTIONAL { :consistency-claim amo:isValidUnless ?rebuttal }
}