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In every communicative act there is a series of operations that are part of the argumentative or reasoning processes. These processes can be carried out by means of different linguistic structures that may or may not be explicit. When these structures are not explicit, other processes are required to understand the arguments. One of those processes is inference and it is necessary first to understand what it is about in order to understand what sorites are.
the inference
Inference can be seen as an operation that establishes a dynamic progression from what is known to admit what is not known. This operation, which is present in both formal and non-formal reasoning, can come from:
- The own experience . Which is what we have of the world and not through progressive reasoning.
- empirical reasoning . What is progressive reasoning within one’s own experience.
- Reasoning of the exact sciences . What is progressive reasoning out of experience?
The inferences made through logical rules or formal reasoning can be established, mainly, through two procedures: deduction and induction.
the deduction
The deduction is a reasoning that goes from the macro to the micro, that is, from general to the particular and respects the principle or axiom of extensionality. In this principle, the validity of the argument is evidenced regardless of the content of the statements. Its basic instrument is the syllogism, which consists of three propositions: the first is a general law, called the major premise. The second is a particular fact, called the minor premise. The third is the conclusion derived from the previous premises, that is, from the inference that follows the principle of extensionality.
Deductive reasoning goes beyond the formal framework through syllogisms that do not adopt the canonical form of the three propositions such as: the sorites, the epiquereme and the enthymeme.
Sorites
One aspect of the complexity of argumentation is that real life arguments are often related. For example, the conclusion of one argument can be the premise of another, so a series of arguments can be linked as a string. What connects the arguments in a chain are the statements that are the conclusion of one argument in the chain and the premise of the next. In simple words, the sorites are composed of two valid premises with which, therefore, the argument is valid.
Example: “The fact is that, between the time the doll was placed on the display platform and the time the theft was discovered, nothing and no one touched it. Therefore, between the time the doll was placed on the platform and the time the theft was discovered, the doll could not have been stolen. It follows, simply and inevitably, that the doll must have been stolen outside of that period» (Ellery Queen, The Dauphin’s Doll).
Parsing a chain argument
In the passage presented there are three statements:
- “The fact is that, between the time the doll was placed on the display platform and the time the theft was discovered, nothing and no one touched it.”
- “Between the time the doll was placed on the platform and the time the theft was discovered, the doll could not have been stolen.”
- “The doll must have been stolen outside of this time period.”
On the other hand, there are two indicators of conclusion that are “therefore” and “it follows… that”. This means that there are two arguments in the passage. Furthermore, the location of the indicators shows that statements 1 and 2 are conclusions. However, statement 1 is not marked, so it is a premise since it is part of one of the two arguments.
Now, the fact that the first statement is a premise can be seen from the fact that the argument from 1 to 2 is logical: if no one touched the doll during that time, it couldn’t have been stolen at that time. However, statement 2 is also a premise because the argument from 2 to 3 is logical: if the doll could not have been stolen during that time, then it must have been stolen at another time. Finally, this passage thus contains a chain of two arguments linked by statement 2, which is the conclusion of the first and the premise of the second.
Evaluation of the deductive argument
This passage is an example of the simplest and most common type of chain argument or sorites, that is, an argument in which two arguments from a single premise are linked in a chain. It should be noted that chain argument processing can be extended as much as desired, such that arguments of this type can be made up of three or more single arguments.
The evaluation of a deductive chain argument is based on the well-known principle that a chain is only as strong as its weakest link. Thus, a deductive string argument will be valid if and only if each of the string arguments is valid. Similarly, a deductive string argument will be invalid if even a single argument in the string is invalid. Therefore, to evaluate a chain of deductive arguments, one only has to evaluate each argument in the chain. If it finds a single invalid argument, the string is broken: the entire string is invalid.
Sources
- Carrillo, L. (2007). Norms, principles and communication strategies .
- Dominguez, S. (1939). Philosophy Text . Notions of logic, theory of science (p. 53).
- Queen, E. (1948). The Adventure of the Dauphin’s Doll. Retrieved from The Big Book Of Christmas Mysteries part 13.
- Trujillo, J. and Vallejo, X. (2007). Theoretical Syllogism , Practical Reasoning and Rhetorical-Dialectical Reasoning.
