Epistemology

[Rand believed] that a philosopher's metaphysics and especially his epistemology trump everything else ... Aristotle's "moderate realism" ... was essentially correct, according to Rand, so it follows that Aristotle's influence must have been good, whereas the irrational epistemology of Plato (and, later, Kant) must have been bad. As Rand wrote in a letter (17 April, 1948), "the crucial difference between Plato and Aristotle lies in their respective Theories of Knowledge and in their views on the nature of reality. That is the root. Their ethics, politics, etc., are the consequences."

[R]eason is an objective means of knowledge; it relies on observation and evidence, with observable reality as the ultimate point of reference. So, when people rely on reason they can interact and resolve conflicts by discussion, persuasion, and debate—that is, by voluntary means. "But when men claim to possess supernatural means of knowledge," Rand says, "no persuasion, communication or understanding [are possible]." If people derive their conclusions from ineffable intuitions or by methods that only they know how to apply, then ... [t]hat leaves force as the only method of "persuasion" ...

A handful of other philosophies besides Objectivism have defended perceptual realism, the theory that we directly perceive things in the external world. But Objectivism is the first philosophy to identify the connection between the primacy of consciousness and the various false theories of the relation between consciousness and existence, among them: representationalism, phenomenalism, idealism, the "sense-data" theory, and others ... Ayn Rand also defended a unique theory of concepts, or abstract ideas. For her, the ability to form concepts was the primary function of the faculty of reason ...

Time and again Spencer appears to confuse epistemology with psychology. By showing what a person is compelled to believe psychologically, Spencer infers that such beliefs enjoy epistemological validity. This is no oversight or slip ...; it is a deliberate method employed throughout his epistemology ... Given that phenomenal knowledge is not illusory, what is the nature of the correspondence between our ideas and unknowable reality? Since we are denied direct access to the noumenal world, how can we segregate subjective beliefs that are worthy of acceptance from those that are not?

[Rand's] epistemology–the base of her philosophy–is wholly untenable to anyone with an understanding of how the mind actually functions. While I believe that we live in an objective universe, none of us can ever know the nature of that reality other than through the subjective processes by which our mind organizes its experiences. We do not learn about the world in the mechanistic fashion of a video camera recording sensory impressions. Rather, we interact with our world, organizing our experiences into categories and concepts by which we make comparisons and contrasts.

Popper's theory of knowledge is distinctive in several respects. He emphasized the criterion of falsification as the distinctive mark of science (although he was prepared to accept certain unfalsifiable ideas as having influenced the development of science). More generally, he developed a unique approach to epistemology, in which he rejected induction as the sole criterion for determining the value of scientific statements and in its place underscored the importance of such statements to resolve problems and survive tests and criticism.

The Objectivist epistemology teaches that humans are conceptual beings. We are aware of the world directly and immediately through sense-perception, but we do much of our thinking at the conceptual level, using abstractions, language, and logic. Our concepts and theories have meaning only insofar as they are grounded in reality, but one cannot see a theory or feel an idea, nor can one perceive, in a single glance, all the facts of reality that validate a theory or idea. The wider and more fundamental the abstraction, the harder it is to experience it ...

Kelley: In epistemology, an issue that interests me is ... the contextual nature of certainty ... It's the question that arises when you make a judgement based on your context ... and there seems to be ample evidence to support [it], and yet later, when your context increases further, you learn that you were wrong. Were you in fact wrong, in which case you were certain of something which wasn't true? Or, is truth in some way relative to context, and if so, how is that consistent with the fact that truth means correspondence to facts that are what they are whether you recognize them or not?