Why use deductive arguments

More specifically, we ask whether the argument is either deductively valid or inductively strong. This point can be expressed also by saying that, in a deductive argument, the premises are intended to provide such strong support for the conclusion that, if the premises are true, then it would be impossible for the conclusion to be false.

An argument in which the premises do succeed in guaranteeing the conclusion is called a deductively valid argument. If a valid argument has true premises, then the argument is said also to be sound. All arguments are either valid or invalid, and either sound or unsound; there is no middle ground, such as being somewhat valid.

The two premises of this argument would, if true, guarantee the truth of the conclusion. However, we have been given no information that would enable us to decide whether the two premises are both true, so we cannot assess whether the argument is deductively sound. It is one or the other, but we do not know which. An inductive argument is an argument that is intended by the arguer to be strong enough that, if the premises were to be true, then it would be unlikely that the conclusion is false.

The argument also will be stronger the more times there were when I did walk by the dog. The argument will be weaker the fewer times I have walked by the dog. It will be weaker if relevant conditions about the past time will be different next time, such as that in the past the dog has been behind a closed gate, but next time the gate will be open.

An inductive argument can be affected by acquiring new premises evidence , but a deductive argument cannot be. For example, this is a reasonably strong inductive argument:.

The distinction between deductive and inductive argumentation was first noticed by the Aristotle B. The difference between deductive and inductive arguments does not lie in the words used within the arguments, but rather in the intentions of the arguer.

It comes from the relationship the arguer takes there to be between the premises and the conclusion. If the arguer believes that the truth of the premises definitely establishes the truth of the conclusion, then the argument is deductive.

If the arguer believes that the truth of the premises provides only good reasons to believe the conclusion is probably true, then the argument is inductive. If we who are assessing the quality of the argument have no information about the intentions of the arguer, then we check for both. That is, we assess the argument to see whether it is deductively valid and whether it is inductively strong.

The concept of deductive validity can be given alternative definitions to help you grasp the concept. Below are five different definitions of the same concept. It is common to drop the word deductive from the term deductively valid :. This article considers conductive arguments to be a kind of inductive argument.

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In each of these examples, the premises may very well be true, but the conclusions make invalid assumptions. Rather, "c" is an overgeneralization. Let's take the Tom Cruise example. Just because Tom Cruise is handsome, does that mean he must be an actor? Who's to say all electricians or writers aren't pretty, too? Inductive reasoning is akin to deductive reasoning.

The main difference is that, with inductive reasoning, the premises provide some evidence for the validity of the conclusion, but not all. With deductive reasoning, the conclusion is necessarily true if the premises are true. With inductive reasoning, the conclusion might be true, and it has some support, but it may nonetheless be false. However, your educated guess can become a hypothesis you could consider fleshing out through research and an abundance of outside sources.

Let's take a look at a few examples of inductive reasoning. After we examine the inductive reasoning, we'll flip it and see what it looks like in the form of deductive reasoning. Notice how each example of deductive reasoning is more sound assuming the first two premises are true?

In each instance, the inductive reasoning may be true. But, they're lacking enough evidence to be universally true. Further samplings would be required. You might also come across abductive reasoning, backward induction, and critical thinking. If you proceed with facts and evidence, your deductive or inductive reasoning can quickly turn into an assumption. And that's what we typically try to avoid in life. A hypothesis, however, is a nice place to start.

This is an idea that can be molded into factuality and follow the lines of deductive reasoning. That might be a road worth considering if you're ever tasked with writing an argumentative essay. Of course, the goal is not to get into an argument but, rather, take a position and present evidence in support of your claim.

For more, enjoy these argumentative essay examples. All rights reserved. What Is Deductive Reasoning? All dolphins are mammals. Deductive reasoning, or deduction, starts out with a general statement, or hypothesis, and examines the possibilities to reach a specific, logical conclusion, according to California State University.

The scientific method uses deduction to test hypotheses and theories. That is, we predict what the observations should be if the theory were correct. We go from the general — the theory — to the specific — the observations," said Dr. Deductive reasoning usually follows steps. First, there is a premise, then a second premise, and finally an inference. A common form of deductive reasoning is the syllogism, in which two statements — a major premise and a minor premise — reach a logical conclusion.

For example, "All men are mortal. Harold is a man. Therefore, Harold is mortal. It is assumed that the premises, "All men are mortal" and "Harold is a man" are true. Therefore, the conclusion is logical and true.