Browse Definitions :
Definition

deductive argument

What is deductive argument?

A deductive argument is a logic construct with two or more premises and a conclusion where if the premises are true then the conclusion must also be true. In philosophy, if the truth of the conclusion is fully established by the premises, then the argument is called valid. If the argument is valid and the premises are true, then the argument is called sound.

Deductive argument example
Deductive argument: 'All dogs have four legs, John's pet is a dog, therefore John's pet has four legs.'

A deductive argument establishes a conclusion to be true by stating two or more true premises that lead to the conclusion being true. A deductive argument can be simply stated as "If A and B are true, then C must also be true." A deductive argument uses deductive reasoning. In a deductive argument the premises have a logical implication.

A simple example of a deductive argument is "All dogs have four legs, John's pet is a dog, therefore John's pet has four legs."

A syllogism is a form of deductive argument with two premises and one conclusion.

Validity and soundness of deductive arguments

A deductive argument is said to be valid if the truthfulness of the premises necessitates that the conclusion be true. A deductive argument is said to be sound if the premises are true.

Invalid deductive argument example
Invalid deductive argument: 'All dogs have four legs, all dogs are animals, therefore all animals have four legs.''

Consider the following example: "All dogs have four legs, all dogs are animals, therefore all animals have four legs." This statement would not be valid because the two premises would not logically require the conclusion to be true.

As another example "All dogs have four legs, Rover is a dog, therefore Rover has four legs." This argument is valid in that if the premises were true, it would mean that the conclusion must be correct. But it is not sound because the premise "all dogs have four legs" is not true, because some dogs through misfortune do not have all their legs.

A good way to determine if an argument is valid and sound is to try to think of counter examples. If no counter examples to the premises can be found it is most likely a sound argument.

An example deductive argument that is both valid and sound is "All dogs are animals, Rover is a dog, therefore Rover is an animal."

Valid and sound argument example
Valid and sound argument: 'All dogs are animals, Rover is a dog, therefore Rover is an animal.'

Exercise caution when evaluating a deductive argument, because it may have true premises and lead to a true conclusion, but the logic is unsound so it is invalid and could cause problems if accepted. Consider "John owns a dog, Rover lives at John's house, therefore Rover is a dog." While those statements may be true, this same logic would lead you to believe that John is also a dog.

Deductive vs. inductive arguments

In philosophy, a deductive argument is contrasted with an inductive argument. Inductive arguments also have premises and a conclusion. The difference is that with a deductive argument, the conclusion must be true, and an inductive argument generally means that the conclusion is only probable. Inductive arguments use inductive reasoning.

An example of an inductive argument is "Most dogs have fur, Rover is a dog, therefore Rover has fur."

In an inductive argument, if the premises would logically lead to the conclusion, it is said that it is strong. If the inductive argument is strong and the premises are true, then it is said to be cognizant. This is like a deductive argument being valid and sound.

The exact distinction between deductive and inductive arguments is not fully accepted by all philosophers. Some may use a slightly different definition. Others believe that there is not a clear distinction between the two and that instead all arguments have different qualities that make this type of categorization difficult or meaningless.

See also: absolute truth, empiricism, Ockham's razor, automated reasoning, root cause analysis, scientific method

This was last updated in October 2022

Continue Reading About deductive argument

Networking
  • SD-WAN security

    SD-WAN security refers to the practices, protocols and technologies protecting data and resources transmitted across ...

  • net neutrality

    Net neutrality is the concept of an open, equal internet for everyone, regardless of content consumed or the device, application ...

  • network scanning

    Network scanning is a procedure for identifying active devices on a network by employing a feature or features in the network ...

Security
  • virtual firewall

    A virtual firewall is a firewall device or service that provides network traffic filtering and monitoring for virtual machines (...

  • cloud penetration testing

    Cloud penetration testing is a tactic an organization uses to assess its cloud security effectiveness by attempting to evade its ...

  • cloud workload protection platform (CWPP)

    A cloud workload protection platform (CWPP) is a security tool designed to protect workloads that run on premises, in the cloud ...

CIO
  • Regulation SCI (Regulation Systems Compliance and Integrity)

    Regulation SCI (Regulation Systems Compliance and Integrity) is a set of rules adopted by the U.S. Securities and Exchange ...

  • strategic management

    Strategic management is the ongoing planning, monitoring, analysis and assessment of all necessities an organization needs to ...

  • IT budget

    IT budget is the amount of money spent on an organization's information technology systems and services. It includes compensation...

HRSoftware
  • ADP Mobile Solutions

    ADP Mobile Solutions is a self-service mobile app that enables employees to access work records such as pay, schedules, timecards...

  • director of employee engagement

    Director of employee engagement is one of the job titles for a human resources (HR) manager who is responsible for an ...

  • digital HR

    Digital HR is the digital transformation of HR services and processes through the use of social, mobile, analytics and cloud (...

Customer Experience
  • chatbot

    A chatbot is a software or computer program that simulates human conversation or "chatter" through text or voice interactions.

  • martech (marketing technology)

    Martech (marketing technology) refers to the integration of software tools, platforms, and applications designed to streamline ...

  • transactional marketing

    Transactional marketing is a business strategy that focuses on single, point-of-sale transactions.

Close