Unless Quotes (page 20)
Experience is never at fault; it is only your judgment that is in error, in promising itself such results from experience as are not caused by our experiments. For having given a beginning, what follows from it must necessarily be a natural development of such a beginning, unless it has been subject to a contrary influence, while, if it is affected by any contrary influence, the result which ought to follow from the aforesaid beginning, will be found to partake of this contrary influence in...
Leonardo da Vinci
In a world in which there is so much to interest, so much to enjoy, and so much also to correct and improve, everyone who has this moderate amount of moral and intellectual requisites is capable of an existence which may be called enviable; and unless such a person, through bad laws, or subjection to the will of others, is denied the liberty to use the sources of happiness within his reach, he will not fail to find the enviable existence
John Stuart Mill