It is in everybody's interest to seek those [actions] that lead to happiness and avoid those which lead to suffering. And because our interests are inextricably linked, we are compelled to accept ethics as the indispensable interface between my desire to be happy and yours.
He who finds though that lets us penetrate even a little deeper into the eternal mystery of nature has been granted great grace. He who, in addition, experiences the recognition, sympathy, and help of the best minds of his times, had been given almost more happiness than one man can bear.
How selfish soever man may be supposed, there are evidently some principles in his nature, which interest him in the fortune of others, and render their happiness necessary to him, though he derives nothing from it, except the pleasure of seeing it.
It is the activity of the intellect that constitutes complete human happiness - provided it be granted a complete span of life, for nothing that belongs to happiness can be incomplete.
And we should consider every day lost on which we have not danced at least once. And we should call every truth false which was not accompanied by at least one laugh.