Are contradictory propositions in the propositional logic still contradictory in the predicate logic?

What seems to be happening here is that contradictory propositions in the propositional logic are contrary in the predicate logic such that, because contrary propositions are not contradictory, contradictory propositions in the propositional logic are not contradictory in the predicate logic.

What is the difference between predicate logic and propositional logic?

Propositional logic is the logic that deals with a collection of declarative statements which have a truth value, true or false. Predicate logic is an expression consisting of variables with a specified domain. It consists of objects, relations and functions between the objects.

What is contradictory logic?

A logical contradiction is the conjunction of a statement S and its denial not-S. In logic, it is a fundamental law- the law of non contradiction- that a statement and its denial cannot both be true at the same time. Here are some simple examples of contradictions.

What makes the proposition false?

This kind of sentences are called propositions. If a proposition is true, then we say it has a truth value of “true”; if a proposition is false, its truth value is “false”. For example, “Grass is green”, and “2 + 5 = 5” are propositions. The first proposition has the truth value of “true” and the second “false”.

Can propositional logic have answers other than true or false?

Propositions can be either true or false, but it cannot be both. Propositional logic consists of an object, relations or function, and logical connectives. These connectives are also called logical operators. The propositions and connectives are the basic elements of the propositional logic.

What are the limitations of proposition logic How can we overcome that using predicate logic?

We can use propositional logic to validate the form of an argument that takes us from premises to a conclusion. We cannot use propositional logic to establish the truth of a proposition that isn’t given as a premise, or which can’t be inferred by the laws of inference.

What are the limitations of predicate logic?

One key limitation is that it applies only to atomic propositions. There is no way to talk about properties that apply to categories of objects, or about relationships between those properties. That’s what predicate logic is for.

How do you tell if a proposition is true or false?

The proposition p ↔ q, read “p if and only if q”, is called bicon- ditional. It is true precisely when p and q have the same truth value, i.e., they are both true or both false.

What is a proposition statement that is always false?

A proposition has only two possible values: it is either true or false. We often abbreviate these values as T and F, respectively. Given a proposition p, we form another proposition by changing its truth value.



2.1: Propositions.

p ¯p
T F
F T


What is the difference between the truth of propositions and the validity of arguments?

Truth and validity are two qualities of an argument that help us to determine whether we can accept the conclusion of argument or not. The key difference between truth and validity is that truth is a property of premises and conclusions whereas validity is a property of arguments.

What are the weaknesses of propositional logic?

A primary weakness of propositional logic is the lack of syntax for representing objects in the domain of interest; propositional logic only permits statements about the domain of interest, e.g., it is not possible to have a symbol for Socrates, rather it is possible only to make statements about Socrates.

What is the difference between proposition and propositional function?

According to Clarence Lewis, “A proposition is any expression which is either true or false; a propositional function is an expression, containing one or more variables, which becomes a proposition when each of the variables is replaced by some one of its values from a discourse domain of individuals.” Lewis used the

What are the limitations of logic discuss any five limitations?

4 Limits Of Logic

  • Partial Truths. Many forms of logic only handle true or false. …
  • Language. Each form of logic represents observations in a formal language of logic. …
  • Uncertainty. Some forms of logic fail to handle uncertainty, although this is studied by a field known as probabilistic logic. …
  • Human Perception.


Why is predicate logic more preferred than propositional logic?

Although predicate logic is more powerful than propositional logic, it too has its limits. A predicate is a boolean function whose value may be true or false, depending on the arguments to the predicate. * Predicates are a generalization of propositional variables.

Why is first-order predicate logic more expressive than propositional logic?

First-order logic is another way of knowledge representation in artificial intelligence. It is an extension to propositional logic. FOL is sufficiently expressive to represent the natural language statements in a concise way. First-order logic is also known as Predicate logic or First-order predicate logic.

What are the advantages of first-order predicate logic over Proposition logic?

Key differences between PL and FOL



Propositional Logic converts a complete sentence into a symbol and makes it logical whereas in First-Order Logic relation of a particular sentence will be made that involves relations, constants, functions, and constants.

Is first-order logic and predicate logic are same?

First-order logic—also known as predicate logic, quantificational logic, and first-order predicate calculus—is a collection of formal systems used in mathematics, philosophy, linguistics, and computer science.

What is the difference between propositional calculus and predicate calculus?

Both work with propositions and logical connectives, but Predicate Calculus is more general than Propositional Calculus: it allows variables, quantifiers, and relations. Given two numbers, we have various ways of combining them: add them, multiply them, etc.

Is propositional logic first-order logic?

First-order logic can be understood as an extension of propositional logic. In propositional logic the atomic formulas have no internal structure—they are propositional variables that are either true or false.

What is predicate in a propositional logic?

A predicate may include variables, and statements with variables become propositions once the variables are assigned values. The universal quantifier is used to express a statement such as that all members of the domain of discourse have property P.

What is a predicate in predicate logic?

Predicates. A predicate is a boolean function whose value may be true or false, depending on the arguments to the predicate. Predicates are a generalization of propositional variables. A propositional variable is a predicate with no arguments.