Final answer:
Mr. Auld's theory was that teaching slaves to read and write would make them unmanageable and of no value to their masters, reflecting the fear and control that slaveholders exerted over enslaved people. This theory underscores the power of education and knowledge in undermining the institution of slavery.
Step-by-step explanation:
Mr. Auld's theory was that teaching slaves to read and write would make them unmanageable and of no value to their masters. He believed that literacy would lead to the slaves becoming discontented and unhappy, ultimately undermining the institution of slavery. This theory reflects the fear and control that slaveholders exerted over enslaved people, recognizing the power that education and knowledge could bring.