Final answer:
Empirical knowledge is gained from direct experience, a key tenet of empiricism. Philosophers like John Locke and Bertrand Russell describe it as knowledge by acquaintance, which is immediate and without inference, placed in contrast to a priori knowledge.
Step-by-step explanation:
Knowledge received or imparted through direct experience is referred to as empirical knowledge, which is a core concept in the philosophy of empiricism. Empiricism is a theory that states that knowledge comes only or primarily from sensory experience. Renowned philosophers such as John Locke and Bertrand Russell have contributed significantly to its understanding, suggesting that at birth, the mind is a blank slate (tabula rasa) and knowledge is built from experiences.
According to British philosopher Bertrand Russell, knowledge by acquaintance is a direct form of knowledge that comes from being directly aware of something, without any need for inference. For example, when one feels pain, they are directly aware of and acquainted with that pain. This kind of knowledge is also known as a posteriori knowledge because it is gained after experience, which contrasts with a priori knowledge that does not necessarily require experiential input.
In addition to philosophy, empirical methods are fundamental in scientific pursuits. The scientific method relies on observation, hypothesis formulation, experimentation, and further observation to confirm or falsify the hypothesis, deriving knowledge that is tentative and subject to revision.