The criterion "Potential Isolation by Brain Damage" refers to the notion that distinct intelligences can be independently affected by brain damage. This means that a specific type of intelligence can be impaired or lost while others remain intact, indicating its unique neurological basis. For instance, a person might suffer damage to a part of the brain responsible for linguistic abilities, losing their capacity to use language, while their mathematical or musical abilities remain unaffected. This criterion supports Gardner's idea that multiple intelligences are separate from each other, each residing in different areas of the brain.

The criterion "Existence of Savants, Prodigies, and Other Exceptional Individuals" highlights the presence of individuals with extraordinary abilities in specific cognitive domains as evidence of distinct intelligences. Savants and prodigies often display remarkable skills in areas like music, mathematics, or art, despite potential deficits in other cognitive functions. This extraordinary proficiency in a particular area suggests that intelligences are modular and independent.

This criterion posits that each type of intelligence must have a core set of cognitive processes or operations. For example, linguistic intelligence involves operations like the ability to use language for expression and comprehension, while logical-mathematical intelligence includes the capacity for deductive reasoning and problem-solving with numbers. The distinct operations characterize each intelligence, making them identifiable and unique. This aspect is crucial as it provides a concrete basis for differentiating between the various intelligences, emphasizing that each is not just a skill but a distinct cognitive domain.

For an ability to be considered an intelligence in Theory of Multiple Intelligence framework, it must be supported by empirical research, particularly through experimental psychological tasks. These tasks should demonstrate the operations and capabilities of the intelligence in question. For instance, tests of musical intelligence might involve discerning pitch or rhythm, while spatial intelligence could be evaluated through tasks involving mental rotation or spatial judgment. The ability to measure and observe these intelligences in controlled experimental settings lends scientific credibility to the concept of multiple intelligences.