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.

Gardner asserts that each intelligence should be measurable to some extent by psychometric tests. However, he also criticizes the overreliance on such tests in traditional intelligence testing. Psychometric support means that standardized tests should be able to reliably measure and differentiate between the various intelligences. This criterion is important for validating the theory within the scientific community and for practical applications, like educational assessments. It ensures that the concept of multiple intelligences is not just theoretical but has practical, measurable implications.

Each intelligence has its own unique developmental trajectory. This means that these intelligences emerge and develop at different stages and rates in an individual's life. For instance, linguistic intelligence develops rapidly in early childhood, while interpersonal intelligence might evolve more significantly during later childhood or adolescence. This criterion underscores the belief that intelligences are not static but evolve with age and experience. The distinct developmental paths of each intelligence imply that educational strategies should be tailored to the maturity level of each intelligence in an individual.

Criterion of evolutionary history and plausibility suggests that each intelligence has evolved to solve specific problems faced by our ancestors. For example, spatial intelligence helped in navigation and understanding the physical environment, while interpersonal intelligence was crucial for social communication and cooperation. This evolutionary perspective implies that these intelligences are rooted in human survival and adaptation needs. It gives the theory an evolutionary framework, suggesting that these intelligences are not arbitrary but have developed in response to real-world demands.