What Is Knowledge and How Do We Acquire It

Definition of Knowledge

Philosophers since the time of Plato have defined knowledge as "justified true belief" (JTB). Three conditions: (1) belief (I believe that P); (2) truth (P is true); (3) justification (I have grounds to consider P true).

In 1963, Edmund Gettier showed that these three conditions are insufficient. "Gettier cases": one can have a justified true belief without having knowledge. Example: you look at a stopped clock showing 3:15. In fact, it is 3:15 now. Your belief is justified (the clock usually shows the correct time), true (3:15), but this is not knowledge — it is a coincidence.

Gettier sparked half a century of discussions on how to improve the definition of knowledge. One approach: add a condition of "non-defeasibility" (your conviction should not depend on false premises). Another: replace "justification" with a "reliable process of belief formation" (reliabilism). There is no unified solution — the problem remains open.

A Priori and A Posteriori Knowledge

A priori knowledge — independent of experience. Mathematics, logic: "2+2=4" does not need to be experimentally verified — it is true by the meaning of the concepts. Kant added: some judgments about the world are also a priori, because they are the form of our perception (space and time).

A posteriori knowledge — dependent on experience. "The Earth revolves around the Sun," "the boiling temperature of water is 100°C" at normal pressure. Verified through observation.

Analytic judgments: true by definition ("A bachelor is an unmarried man"). Synthetic: add new information ("Bachelors are happier than married men" — this needs to be checked).

Rationalism vs Empiricism

Rationalists (Descartes, Spinoza, Leibniz): the source of genuine knowledge is reason. The senses deceive; only reason provides necessary and universal truths. Innate ideas (ideas of God, mathematical axioms) — not from experience.

Empiricists (Locke, Berkeley, Hume): knowledge from experience. There is nothing in the mind that was not first in the senses. No innate ideas. The mind is a blank slate.

Kant: synthesis. Experience is necessary, but reason structures experience through a priori categories. Knowledge = form (reason) + content (experience).

Realism, Idealism, Pragmatism

Realism: the world exists independently of our cognition. The task of science is to discover its structure, which is "out there," independent of us.

Idealism (Berkeley): "to be is to be perceived" (esse est percipi). There is nothing except consciousness and its contents. Extremely counterintuitive, but logically consistent.

Pragmatism (Peirce, James, Dewey): knowledge is not a copy of reality, but an instrument of successful action. "True is what works." This is not "everything is subjective" — it is a shift of the criterion from correspondence to reality to practical effectiveness.

Sociology of Knowledge and Virtue Epistemology

Modern epistemology is expanding into the social sphere. Social epistemology (Alvin Goldman): how is the social production of knowledge organized? Which institutions — science, media, markets — are reliable? How do trust and the testimony of others influence our beliefs?

Virtue epistemology (Linda Zagzebski): the analogue of virtue ethics in the theory of knowledge. Instead of focusing on the rules of acquiring knowledge — on intellectual virtues: open-mindedness, intellectual honesty, epistemic humility, curiosity. A good thinker is not one who follows the rules, but one who has developed a good intellectual character.

A question for reflection: Evaluate your thinking by the criteria of epistemic virtue: openness to revising beliefs, honesty in assessing counterarguments, humility regarding the limits of your own knowledge. Where are you strong? Where is there room for growth?