Here's a breakdown:
* Propositions: These are statements that can be either true or false. For example: "The sky is blue." "All dogs are mammals."
* Inferences: These are conclusions drawn from a set of propositions. For example, if we know that "All dogs are mammals" and "Fido is a dog," then we can infer that "Fido is a mammal."
* Validity: This refers to the soundness of an inference. A valid inference is one where the conclusion logically follows from the premises.
In essence, logic is the study of how to reason correctly. It provides a framework for analyzing arguments and determining whether they are sound or not.
Logic can be applied to many different areas, including:
* Mathematics: Logic is the foundation of mathematics, providing the rules for deductive reasoning.
* Computer science: Logic is used in the design of computer programs and systems.
* Philosophy: Logic is a fundamental tool for philosophical inquiry.
* Everyday life: Logic helps us to make sense of the world around us and to make informed decisions.
So, to answer your question more succinctly, logic pertains to reasoning, argumentation, and the structure of knowledge.