He reflected that good eyes are full of light. We cannot see a thing without it. And if you live in a place where the sun shines all the time, where the weather is always pleasant, there are probably too many people living there to enjoy it. But for eyes, more light is always good. It is the same with the heart.
Good hearts are full of light.
Don't believe Thomas Hardy, or rather seek a heart of light, and let that light shine. Watch the sunrise. Light a candle in the dark. Thank God for light. Bring less heat and more light.