The deductive argument is that the law prescribes the absolute coexistence of the premises and conclusion ensuring that the latter represented in the premises. The major premise is general and particular conclusion.

Syllogisms are a form of deductive reasoning consisting of two propositions as premises and a conclusion, latter being necessarily deductive inference from the other two.

The figures are the ways that magazine the syllogism according to the position of the middle term in the premises. There are four figures which are the following:

1^a figure 2ª figure 3ª figure 4ª figure

M it P P it M M it P P it M

S it M S it M M it S M it P

---------- ----------- ----------- ------------

S it P S it P S it P S it P

The modes are the configurations of each figure, according to the propositions are A, E, I, O; i.e., taking into account the quantity and quality of the proposals the most common are:

Figure 1: BARBARA, CELARENT, DARII FERIO.

2 nd figure: CESARE, CAMESTRES, FESTINO BAROCO.

3 rd. figure: DARAPTI, FELAPTON, DISAMIS, DATISI, BACARDO, FERISON.

Figure 4: BAMALIP, CAMENES, DIMATIS, FESAPO, FRESISON.

Structure for validity of an argument

Modus mode ponens or affirmation of the antecedent

1.A B 2.A 3.B 1,2mp

1. A B 2. A 3.B 1,2mp

1. A B 2.A 3. B 1,2mp

1. A B 2. A 3. B 1,2mp

Modus tollens or denial of the consequent

Disjunctive syllogism or negation of the disyunto

Hypothetical syllogism or transitivity conditional

Inductive argument

One inductive argument is which, starting from the observation of a property defined in one sufficient number of individuals of a particular class, generalizes the observed property at the conclusion and attributed it to all members of that same class. This generalization applies both to cases observed as for all of their species not observed. Unlike deductive arguments, whose conclusion does not provide new information and why his conclusions are necessary, inductive arguments in its conclusion offer us new information, i.e. information not included in the premises, and therefore its conclusion is likely.

Abductive argument

Is a type of reasoning that, from the description of an event or phenomenon, offers or becomes a hypothesis that explains the analysis of the case. According to Aristotle, abductive reasoning is syllogisms where the premises only provide some degree of probability to the conclusion.

Argument constructive

An affirmative constructive speech is one that constructively defends an assertion or argument.

Fallacies

One fallacy is not valid reasoning or wrong but with appearance of correct reasoning. It is an (fallacious) misleading or erroneous reasoning, but intends to be convincing or persuasive. All the fallacies are reasoning that do not comply with any logical rule. Thus, for example, argued in a fallacious manner when in time of present reasons adequate against the position that defends a person, it is attacked and discredits: goes against the person without refute what he says or said. The logical fallacies are usually classified in formal and non-formal.

Non-formal fallacies

Non-formal fallacies are arguments in which contributing the premises is not suitable to justify the conclusion that we want to reach. You want to convince not providing good reasons but appealing to non-relevant elements, or even irrational. . When the premises are accurate information, they do, in any case, by a different conclusion to which is intended.

The above example of fallacy is a case of non-formal fallacy: descalificamos the person who argues rather than refutes your reasons. The list of non-formal fallacies is long; some are as follows.

Fallacy ad hominem (directed against the man)

Reasoning that, instead of presenting adequate reasons to rebut a certain position or conclusion, is attacked or discrediting the person who defends.

Fallacy ad baculum (appeal to the stick)

Reasoning in which to establish a conclusion or position provide no reasons but that is traversed to the threat, the force or fear. It is an argument that allows you to overcome, but not convincing.

Ad verecundiam fallacy (appeal to authority)

Reasoning or discourse in which defends a conclusion or opinion not providing reasons but appealing to some authority, most or any custom.

It must be observed that in some cases it may be legitimate to take an authority recognized in the subject; but it is not always a guarantee.

Fallacy ad populum (aimed at the town causing emotions)

Reasoning or discourse in which omitted the appropriate reasons and reasons not connected with the conclusion but known to be exposed will be accepted by the audience, awakening feelings and emotions. It is a demagogic or seductive argument.

Fallacy ad ignorantiam (by ignorance)

Reasoning which aims to defend the truth (falsity) of a statement by the fact that not can prove otherwise.

Formal fallacies

Argument ad Baculum (appeal to force)

Appeal to force is committed when it appeals to force or the threat of force to bring about the acceptance of a conclusion. It usually turns to it when they fail tests or rational arguments.

Example 1

A father can end a discussion with their children or Lady saying, (... here is what I say, because I am bringing home money!). Course that the head of the household is the father, but from the point of view of logic argue that the decision that the proposed is good only because the brings home money is wrong, other members of the family may have better ideas and have to be heard.

Non pro Causa (false cause)

Cause this fallacy consists of error as cause of an effect something that is not the real cause. It is not difficult to see that the mere fact of the coincidence or temporal succession is not enough to establish a causal connection between the two events.

Example 1

Must reject the claim of some aborigines that touching the drum the Sun reappears after an eclipse, even though it can offer as proof the fact that whenever the drum is played during the eclipse the Sun reappeared.

Equıvoco

Most of the words have more than one literal meaning; for example, the word (peak) which can designate a tool to work the land, or the mouth of a bird. If we clearly distinguish these different senses, does not arise any difficulty. But if we confuse different meanings that may have a word or phrase and use it within the same context with its various meanings without realizing it, then we are using it in a way equıvoca.

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