Sources of knowledge refer to the means through which a person is acquiring knowledge.
Knowledge means skills, facts, or information acquired by any person, through experience or education. If someone is curious, then he will look for some sources for knowledge to clear things out. Similarly, if a person has any doubt about any topic, s/he will search for answers in various ways. These ways act as sources of knowledge.
There can be many sources of knowledge transfer. Sensory perception is one such way. Humans have five senses, and these are one of the gateways of knowledge. These senses help to get primary information about any person, event, object, or other such things.
Logical reasoning is the other way to do so. Humans have evolved over a period of time. Humans infer various things from different methods, like abstract thinking, deductive reasoning, finding relationships between variables and events, and many more.
A categorical syllogism is also one of the sources. In this method, the conclusion is deduced from two or more propositions. This method has three components. The first is the major premise, the second one is the minor premise, and the last is the conclusion.
The other sources are inductive reasoning, experience, authority, naturalistic inquiry, trial and error, etc.