Human happiness seems to consist in three ingredients; action, pleasure and indolence. And though these ingredients ought to be mixed in different proportions, according to the disposition of the person, yet no one ingredient can be entirely wanting without destroying in some measure the relish of the whole composition.
David HumeIn our reasonings concerning matter of fact, there are all imaginable degrees of assurance, from the highest certainty to the lowest species of moral evidence. A wise man, therefore, proportions his belief to the evidence.
David Hume