Final answer:
The person was seen as intelligent because he had memorized many court cases, yet lacked original thought and wisdom, perhaps due to complacency from wealth and a lack of challenging work. The cases likely refer to historical legal decisions important to the common law tradition.
Step-by-step explanation:
The individual under discussion was considered intelligent by most people because he had memorized a vast number of court cases stretching back to King William's time, which likely created the impression of a highly educated and wise individual.
Nonetheless, the memorization of court cases does not necessarily correlate with having original thoughts or insights, which are required for true intellectual mastery and wisdom. It seems that this individual, although knowledgeable of legal history and precedent, lacked the capacity for innovative legal analysis or the ability to apply this knowledge to new and complex situations. As for the court cases mentioned 'since King William's time,' they likely refer to significant legal decisions spanning several centuries which have contributed to the common law tradition, particularly influential in jurisdictions such as Great Britain and the United States.
Why the individual was both less busy and less wise than others might relate to a lack of engagement with challenging work or a failure to apply and expand upon the knowledge possessed, potentially due to complacency or over-reliance on inherited wealth and status that diminished the need or desire for professional ambition and growth. This complacency might also contribute to an absence of original thoughts or insights, as there is little incentive to cultivate such qualities without personal or professional challenges to overcome.