Formal logic and its basic laws
Logic - the science of methods, laws and formsthinking. Formal logic was developed by the ancient Greeks long before our era. It was the Greeks who first built a democratic society, where decisions and laws were adopted at people's congregations. They have, at a primitive level, created the science of conducting litigation. And the favorite occupation of aristocratic youth was the discussions with philosophers. Hence the universal love for the development of theoretical sciences. The Greeks simply needed a teaching on how to cost scientific evidence.
The first course of the foundations of logic was developed by Aristotle. He drew attention to the fact that any reasoning is based on general laws, the violation of which leads to erroneous conclusions. The formal logic of Aristotle was based on such laws:
- If judgments are affirmative, the conclusion drawn from them can not be negative.
- If one of the statements is negative, then the general conclusion will always be negative.
Hence it follows that formal logic isknowledge of the principles and laws of effective, correct construction of reasoning, taking into account the form of their construction (ways of connecting separate parts of the general reasoning).
All phenomena and objects are interconnected. Links can be objective or subjective, general or private, necessary or accidental. The most essential of these links are called laws. All of them reflect the same reality, therefore, can not contradict each other in any way. All the laws of human thought are connected with the laws of the development of nature.
The laws of thought represent a stable inner connection between thoughts. If a person can not connect his thoughts, he will not come to the right conclusion and will not be able to convey it to others.
Basic laws of formal logic- these are the laws of consistency, identity,the exclusion of the third and the law of sufficient grounds. The development of the first three belongs to Aristotle and Plato, the latter to Leibniz. Violations of these laws (especially the first three) leads to contradictions, making it impossible to distinguish truth from lies. The latter law is less normative and is applied more restrictively.
The non-basic laws of logic are rulesoperating judgments and concepts, obtaining a true conclusion in the syllogism, increasing the probability of inference conclusions inductive and transductive nature.
The law of consistency means that thinking should not be contradictory, but must reflect the qualitative certainty of things.
The law of the excluded third prescribes notto seek between the two contradictory but true statements something third, and to recognize the truth of only one of them. One of the components of the contradiction is necessarily true.
The law of identity formal logic treats asthe requirement of thinking accuracy, that is, under any term you need to accurately understand its definition and meaning. The essence of concepts and judgments can not be distorted at will.
The law of good reason is,that any true thought must be justified by other true thoughts, and it is impossible to justify false thoughts. The development of judgments should reflect a causal relationship. Only in this case can its validity be proved.
Logical form of thought and ways of determining the formsany thoughts are expressed with the help of logical terms, to which the unions "and", "or", "if ..., then ...", deny "it is not true that" ("not"), the words "some", " all "(" none "), a bunch of" essence "(in the meaning of" is "), etc. Identify the logical form of judgment can be distracted from the meaning of the terms illogical, which enter into the verbal expression of this judgment. In other words, formal logic expresses the structure of thought. The logical form is always informative and informative.
Depending on their forms, thoughts are divided into classes: concepts, inferences and judgments. A concept is a thought that generalizes objects on the basis of their basic characteristics. Judgment is a thought that affirms the existence (absence) of the state of affairs. Inference is a thought reflecting the acquisition of knowledge expressed in judgments from other knowledge.