"As for everything else, so for a mathematical theory: beauty can be perceived but not explained"

In this quote, mathematician Arthur Cayley is recommending that appeal is a subjective concept that can be observed and valued, but not fully understood or justified. He compares this idea to a mathematical theory, which can likewise be viewed and admired for its elegance and simplicity, but can not be totally explained or comprehended. This highlights the concept that there are certain aspects of life, such as beauty and mathematical theories, that may be beyond our total understanding. It also recommends that there is a particular level of secret and wonder in these principles, and that perhaps their real essence lies beyond our grasp.