An excerpt from chapter 2 on Sense Perception & Volition from Objectivism: The Philosophy of Ayn Rand by Leonard Peikoff.
Implicit in the foregoing is a principle essential to the validation of the senses and, indeed, to all of epistemology. I mean Ayn Rand’s crucial principle that consciousness has identity.
Every existent is bound by the laws of identity and causality. This applies not only to the physical world, but also to consciousness. Consciousness—any consciousness, of any species—is what it is. It is limited, finite, lawful. It is a faculty with a nature, which includes specific instrumentalities that enable it to achieve awareness. It is a something that has to grasp its objects somehow.
The fact that consciousness has identity is self-evident; it is an instance of the law of identity. Objectivism, however, stands alone in accepting the fact’s full meaning and implications. All the standard attacks on the senses—and wider: all the modern, Kant-inspired attacks on human cognition as such—begin with the opposite premise. They begin with the premise that …
Read the rest in Objectivism: The Philosophy of Ayn Rand.