Nature of Logic

• Reasoning, when expressed in language, is called an argument.
• In an argument, premises are the known data, and the conclusion is the new knowledge.
• Reasoning is divided into deductive and inductive.
• Deductive inference draws a conclusion from given premises, with the conclusion being no more general than the premises.
• Inductive inference forms a general conclusion based on observed facts, with the conclusion being more general than the premises.
• Logic provides systematic knowledge of principles regulating reasoning to realize truth and avoid error.

Nature of Logic

• Logic is concerned with mediate knowledge, not immediate knowledge.
• Knowledge involves a system of ideas, their correspondence with existing things, and a belief in this correspondence.
• Mediate knowledge is derived through other knowledge sources like inference, testimony, and authority.
• Immediate knowledge comes directly from perception, both external and internal.
• Logic is primarily concerned with mediate knowledge because it requires proof to establish validity.

Forms of Knowledge

• Knowledge exists in two forms, immediate and mediate.
• Logic is concerned with both formal and material truth.
• Every material object has two aspects: form and matter.
• There is a close relationship between form and matter, since matter can't exist without form and vice versa.
• Similarly, thought also has form and matter.
• Truth can mean consistency among thoughts or correspondence between thoughts and reality.
• Formal truth relates to self-consistency among thoughts.
• Material truth involves correspondence of thoughts with actual facts.
• A statement that is materially true is also formally true, but the reverse is not always the case.

Logic in Western Thought

• Western Logic divides into Formal and Material Logic based on formal vs. material truth.
• Formal Logic aims for formal truth and deals with consistent thoughts, assuming premises are true.
• Logic examines only if argument rules are followed and conclusion follows from premises.
• Material Logic seeks material truth and deals with thoughts that align with the world's facts.
• Examines whether premises are facts and if the conclusion corresponds to reality

Logic in Indian Thought

• Does not have a distinction between Formal and Material
• Formal truth and material truth are complementary aspects of essentially indivisible truth.

Logic as a Discipline

• Determines the regulative principles of correct thinking.
• Prescribes those principles to avoid thinking errors.
• An argument is formally true if the rules are followed in drawing the conclusion.
• Materially true if its propositions align with the world's actual facts.

Logic - Science and Art

• Logic is a science that sets the ideal of Truth and regulates thinking/reasoning/subsidiary processes to attain formal and material truth and avoid errors.
• Many logicians define logic as a system for the 'art of reasoning'.
• But this isn't accepted because logic not only has a practical applications, it also possesses theoretical frameworks,
• Additionally, Logic has processes external to reasoning, such as: definition, division and classification'
• Furthermore, Logic is more defined as a method of 'valid' reasoning, which is implicit, rather than explicitly stated.

How Logicians Define Logic

• Logic is also determined to be the science of argumentation by Albertus Magnus
• This definition is said to be open for objection; it recognizes only theoretical aspects and overlooks practical applications
• Others define it as the 'science as well as art of reasoning' - by Whately
• This definition has been objected to on the grounds that it recognizes subsidiary processes. It also misses the description of describing "valid" reasoning".

Nature of Logic

• Logic examines the 'estimation of evidence (Mill)
• The definition may be analyzed in terms of it being a 'science of proof' , but also it may be defined as a 'science of discovery'
• In all scenarios, is is an essential to recognize the theoretical and practical aspects of logic.

Scope of Logic

• Scope of a science indicates the subject-matter which the science concerns itself.
• Generally, logic is a science of thought, but in reality Logic is also deals with a range of components, such as: Perception, Memory etc.
• Logic is primarily concerned with the problem of proof, and requires a test to test validity
• Additionally, Logic focuses on reasoning - the mental process of something known, to something unknown
• But note: Logic IS NOT concerned with origin. It is concerned with correct vaild reasoning, but not its origin.

Thinking

• Thinking involves both the processes and the products. It is psychologists who are concerned with the processes of thinking.
• Judgement is a part of thought.
• Reasoning/Inference is of two kinds: Deductive and Inductive.
• Logic is concerned with valid reasoning and truth - both formal and material.
• It requires auxiliary processes like definition, division, naming, classification etc.

Modern vs ancient Logic

• Logic has also be shown to be a useful tool to aide mathmatics, such as computer science.
• The study of logic sharpens the intellect.
• From an older perspective, logic was thought to be from 'Arisotle', that was said to develope around the Greek philosopher, and was more or less limited to the type of "syllogistic reasoning."
• However, Modern logic represents has newer phases which focus more on development, dating sometime around the 17th century, related to the growth of mathmatics
• People like George Boole have had impacts on logit, known as symbolic logic'.
• However, note that despite the changes, and differences, both logics have developed together.

This lesson explores the concept of logic, differentiating between mediate and immediate knowledge. It emphasizes that logic is concerned with mediate knowledge, which is derived through inference, testimony, and authority, as opposed to immediate knowledge gained directly from perception.