The best Quotations

Do you know the writers of the following quotations?

Quotation No one is rich whose expenditures exceed his means, and no one is poor whose incomings exceed his outgoings. - writer
Quotation There have been many definitions of beauty in art. What is it? Beauty is what the untrained eyes consider abominable. - writer
Quotation To be good is noble, but to teach others how to be good is nobler and less trouble. - writer
Quotation I have never wished to cater to the crowd; for what I know they do not approve, and what they approve I do not know. - writer
Quotation You must do the thing that you think you cannot do. - writer
Quotation Most people would rather die than think: many do. - writer