René Descartes, a French philosopher, is credited with the famous statement "Cogito, ergo sum" in his work "Discourse on the Method".

The correspondence theory of truth states that a statement is true if and only if it corresponds to or accurately represents reality.

Friedrich Nietzsche, a German philosopher, argued that truth is subjective and relative to the individual, and that there is no objective or universal truth.

The coherence theory of truth states that a statement is true if and only if it is consistent with and supported by other beliefs and evidence.

Immanuel Kant, a German philosopher, proposed the idea of "transcendental idealism", arguing that the mind structures and organizes our experience of reality.

The pragmatic theory of truth states that a statement is true if and only if it is useful in achieving a desired outcome or goal.

Thomas Aquinas, a medieval philosopher and theologian, argued that truth is revealed through divine inspiration or intuition.

The skeptical argument against the possibility of knowledge combines all of the above options, questioning the reliability of our senses, the influence of subjectivity, and the lack of absolute proof for the truth of our knowledge.

John Rawls, an American philosopher, proposed the idea of "the veil of ignorance" in his work "A Theory of Justice", arguing that we should make decisions as if we were unaware of our own personal circumstances.

The foundationalist theory of knowledge holds that knowledge is based on self-evident truths or axioms that do not require further justification.

John Locke, an English philosopher, argued that knowledge is justified true belief.

The coherentist theory of knowledge holds that knowledge is based on the coherence of our beliefs with each other.

Karl Marx, a German philosopher and sociologist, argued that knowledge is a social construction, shaped by our interactions with others and our cultural context.

The fallibilist theory of knowledge holds that knowledge is always provisional and subject to revision.

Francis Bacon, an English philosopher and scientist, argued that knowledge is power.