Definition Deductive reasoning is a method of reasoning which argues from a general premise to deduce a more specific conclusion. It is the reasoning which builds deductive argument. Together with inductive reasoning, they are the two basic forms of valid reasoning. Deductive reasoning is generally used in the argumentative essays and is widely considered to be the most persuasive and most precise way to build an argumentative essay. Deductive arguments could be valid or invalid, sound or unsound, but are never false nor true.A “valid” deductive argument is which the conclusion necessarily follows from the premise. There are three basic stages of deductive reasoning: the premise, the evidence, and the conclusion. We use deductive reasoning quite often in our life. And if you are interested in the detective novels, you can finds many places using the method of deductive reasoning. Sherlock Holmes written by Arthur Conan Doyle is one of the most typical detective story which uses a lot of the method of deductive reasoning.
Three steps of Deductive reasoning Deductive reasoning has three steps: premise, evidence and conclusion. The premises are basic facts or factual information used for drawing the conclusions. The premises are the major assumptions of deductive reasoning. There may be several premises in deductive reasoning. The premises are the assumptions the argument is built on; or to look at it another way, the reasons for accepting the argument. A premise often begins with words such as assume, since, because…… The evidence is the information you provide to help you draw the conclusion, it could be some specific information you are analyzing or something you have observed. If we say that the premises are general, then the evidences are some more specific information. The premise and evidence must be in accordance with the objective reality, or there won’t have a right conclusion. So, we say a deductive argument is sound only if it is valid and the premises are all the general facts. So, in the process of writing an argumentative essay, first you need to introduce the factual information as a premise and then bring the evidence that helps you to draw the conclusion. The conclusion is the final judge of the specific information based on the basic facts, the result which you are trying to prove. In many cases, a deductive essay may have several potential conclusions. But there is only one final conclusion under a particular argument. And this conclusion could also be a premise or assumption in any other arguments.
Some Examples of the Three Steps 1. Premise: Every X has the characteristic Y. Evidence: This thing Z is X. Conclusion: Therefore, Z has the characteristic Y. 2. Premise: All men could die. Evidence: Socrates is a man. Conclusion: Therefore, Socrates could die. 3.A simple deductively valid argument: Everything made of copper conducts electricity. (Premise) This wire is made of copper. (Premise) This wire will conduct electricity. (Conclusion) 
Characteristics of Deductive Reasoning (1) There is necessary connection between the general facts of the premise and the specific information of the evidence. (2) Whether the conclusion is sound is judged by the general premises. If the general premises can correctly reflect the laws of things that objectively exist and the premise and conclusion together can reflect the correct relations between two things, we can say the conclusion is correct. (3) In the process of deductive reasoning, the logic thingking is from general to specific, from abstract to concrete.
To Write A Deductive Essay Although when we first thinking about the deductive reasoning, we think it is about police works, investigating report and science research, it is also very important in literatures. Deductive reasoning takes the MOST REASONABLE, LIKELY path, but is not necessarily fool-proof. That is why it is very important for the evaluation of the knowledge level of students in the courses. Bear in mind the following tips which are the keys to a good deductive essay:
· A good deductive essay need to be very clear and focused.
· Each paragraph of the essay is supposed to focuses on one particular aspect or point of view and use details and examples properly so as to lead to a specific conclusion.
· The support for one’s conclusion is the most important factor. Without supporting one’s point, the conclusion is weak.