"To achieve the broad and exhaust the subtle, to be extremely wise and to achieve the golden mean" is a classic sentence from the book "The Doctrine of the Mean". Its meaning can be explained as follows:

"To achieve the vast and exhaust the subtle." "Subtle": committed to exploring the vast scope of things broadly and pursuing a detailed understanding of things. This sentence emphasizes a comprehensive understanding of the world and an in-depth study of details.

"Extremely wise and moderate": Pursuing extreme wisdom and outstanding talents, but insisting on the golden mean. This sentence emphasizes the need to maintain balance and stability while pursuing excellence, and avoid being too extreme or extreme.

The meaning of the whole sentence can be understood as pursuing broad knowledge and in-depth understanding, while maintaining balance and stability in the process of pursuing excellence. This sentence embodies the golden mean in Confucianism, which is to pursue moderation and balance in all aspects and avoid being too biased to one side in order to achieve a state of harmony and perfection.