In logic, there are various types of arguments, the most well-known of which are "deductive" and "inductive." There are one or more premises but only one conclusion in an argument. The term "argument" is used broadly to describe any sequence of statements (or propositions) that aims to prove or disprove something.
Deductive arguments use a method called "syllogism," which is the study of logical consequences; that is, using logic to reach conclusions by true steps.
Inductive arguments do not use syllogisms but rather probability and evidence of some kind. We can say that inductive arguments show that something is likely to be true because it has been found to be true in many cases.
Both deductive and inductive arguments aim to prove or disprove a claim or hypothesis. The difference between them is based on how they do so: deductively, we start with certain assumptions about reality and work our way toward conclusions; inductively, we look at examples of reality and then make predictions about what will happen next, without necessarily starting from certainty.
These are just two examples of many. In fact, there are very few things that cannot be described as either inductive or deductive arguments. The key is to understand why certain methods work better than others.
To obtain a verified conclusion, deductive reasoning employs supplied facts, premises, or established general laws. Inductive logic or reasoning, on the other hand, entails forming generalizations based on behavior seen in specific circumstances. Deductive arguments are either true or false. Inductive arguments are either true or false, but not necessarily both. A deductively proven argument may still be an inductive argument if the evidence used to prove it is derived from a limited sample of cases; thus, it can only be said that the argument is inductive, not deductive.
Deductive arguments consist of two main parts: a conclusion and a reason. The reason must be capable of proving the conclusion. This reason should be as simple as possible because complex reasons make the argument difficult to verify or refute. For example, when using syllogisms as deductive arguments, the reason must be a categorical statement (a statement that can only be "yes" or "no") or a hypothetical statement (a statement that can only be "if...then...").
Inductive arguments usually also include two parts: a hypothesis and a conclusion. However, instead of looking at what needs to be proved, we look at what has been observed before. If there is a pattern to how things are related, then we can assume that this relationship will continue into the future, and make a generalization about all instances of that phenomenon.
An argument in logic involves (at least) two declarative phrases (or "propositions") known as the "premises" (or "premisses"), as well as another declarative sentence (or "proposition") known as the conclusion. The fundamental argumentation framework consists of two premises and one conclusion. These are often called a "two-premise argument" or simply an "argument".
A formal argument is one that follows a specific structure. This structure requires that there be two premises, which explain why someone should believe the conclusion. For example, here is an argument for why people should vote for Barack Obama:
Premise 1: If Obama becomes president, then more jobs will be created. Premise 2: Obama is going to create many more jobs than Hillary Clinton. Conclusion: Therefore, people should vote for Obama.
In order for this argument to be valid, the two premises must be true and must lead to the conclusion. For example, consider an argument where one of the premises is false:
False: Romney will create many more jobs than Obama.
In this case, the argument is not valid because the premise has been violated - the argument relies on both premises being true.
A deductive argument states that the truth of the conclusion follows logically from the premises. Consider the following argument: Because bats can fly (premise=true), and all flying creatures are birds (premise=false), bats must be birds (conclusion=false). This argument is called "deductive" because it follows a strict set of logical steps or "rules" for proof.
An inductive argument does not have a strict set of rules to follow. With inductive arguments, we make assumptions about what has been proven before, and then try to show that those assumptions hold for the new information being considered. Consider the following argument: All birds are living creatures (assumption) so every bird is alive (conclusion). This argument is called "inductive" because we are using the idea that something has been shown to be true to conclude that it must be true about another thing. Induction can only prove general truths about groups of things; it cannot prove specific facts about any one item.
Logical arguments can be either inductive or deductive. Inductive arguments do not guarantee that new information will have the same result as previous information. For example, considering only animals on land, trees would not be included in an induction about plants. However, even though trees are not plants they do still share some similarities with them. So assuming that all plants have these similarities and then looking at trees might help us learn more about plants.