„Everybody in the world is seeking happiness—and there is one sure way to find it. That is by controlling your thoughts. Happiness doesn't depend on outward conditions. It depends on inner conditions.“
Source: How to Win Friends and Influence People
— Leo Tolstoy Russian writer 1828 - 1910
— J.C. Ryle Anglican bishop 1816 - 1900
Source: A Call to Prayer
„The happiness of those who want to be popular depends on others; the happiness of those who seek pleasure fluctuates with moods outside their control; but the happiness of the wise grows out of their own free acts.“
„Remember happiness doesn't depend upon who you are or what you have; it depends solely on what you think.“
— Dale Carnegie American writer and lecturer 1888 - 1955
As quoted in Plenty of Time to Sleep When You're Dead : A Compilation of Life-changing Quotes (2006) by Richard Caridi
As quoted in Sprituality in a Materialistic World (2008) by Leslie Klein
Variant: Remember happiness doesn't depend on who you are or what you have; it depends solely upon what you think.
— Sri Chinmoy Indian writer and guru 1931 - 2007
Songs of the Soul (1971)
Context: Science depends on outer experiment. Spirituality depends on inner searching and seeking. A scientist discovers the power that very often threatens even his own life. A spiritual seeker discovers the power that guides and moulds his life into a life of divine fulfilment.
— T. B. Joshua Nigerian Christian leader 1963
On the secret of success - "TB Joshua Sends Pastor Chris Member To School" https://archive.is/20130628101340/www.allvoices.com/contributed-news/3995918-tb-joshua-sends-pastor-chris-member-to-school All Voices (August 25 2009)
„Staying as I am, one foot in one country and the other in another, I find my condition very happy, in that it is free.“
— René Descartes French philosopher, mathematician, and scientist 1596 - 1650
Me tenant comme je suis, un pied dans un pays et l’autre en un autre, je trouve ma condition très heureuse, en ce qu’elle est libre.
Letter to Elisabeth of Bohemia, Princess Palatine (Paris, June/July 1648)
— Tulsidas Hindu poet-saint 1532 - 1623
Quoted in "A Garden of Deeds: Ramacharitmanas, a Message of Human Ethics" which principle Mahatma Gandhi adopted to give a national leadership motto, in P.7
— Aristotle Classical Greek philosopher, student of Plato and founder of Western philosophy -384 - -321 BC
An interpretative gloss of Aristotle's position in Nicomachean Ethics book 1 section 9, tacitly inserted by J. A. K. Thomson in his English translation The Ethics of Aristotle (1955). The original Greek at Book I 1099b.29 http://perseus.uchicago.edu/perseus-cgi/citequery3.pl?dbname=GreekFeb2011&getid=0&query=Arist.%20Eth.%20Nic.%201099b.25, reads ὁμολογούμενα δὲ ταῦτ’ ἂν εἴη καὶ τοῖς ἐν ἀρχῇ, which W. D. Ross translates fairly literally as [a]nd this will be found to agree with what we said at the outset. Thomson's much freer translation renders the same passage thus: [t]he conclusion that happiness depends upon ourselves is in harmony with what I said in the first of these lectures; the words "that happiness depends upon ourselves" were added by Thomson to clarify what "the conclusion" is, but they do not appear in the original Greek of Aristotle. Rackham's earlier English translation added a similar gloss, but averted confusion by confining it to a footnote.
Variant: Happiness depends upon ourselves
Source: See http://www.mikrosapoplous.gr/aristotle/nicom1b.htm#I9 for the original Greek and Ross's translation; Thomson's translation can be viewed on Google Books https://books.google.com/books?id=9SFrNWmO654C&dq=%22happiness+depends+upon+ourselves%22+aristotle&focus=searchwithinvolume&q=%22happiness+depends+upon+ourselves%22+.
Source: Rackham's translation of this passage is available here http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0054%3Abook%3D1%3Achapter%3D9%3Asection%3D8
"Jubal Harshaw" in the first edition (1961); the later 1991 "Uncut" edition didn't have this line, because it was one Heinlein had added when he went through and trimmed the originally submitted manuscript on which the "Uncut" edition is based. Heinlein also later used a variant of this in The Cat Who Walks Through Walls where he has Xia quote Harshaw: "Dr. Harshaw says that 'the word "love" designates a subjective condition in which the welfare and happiness of another person are essential to one's own happiness.'"
Source: Stranger in a Strange Land (1961; 1991)
„Happiness and suffering, however extreme, are mental events. The mind depends upon the body, and the body upon the world, but everything good or bad that happens in your life must appear in consciousness to matter. This fact offers ample opportunity to make the best of bad situations—changing your perception of the world is often as good as changing the world—but it also allows a person to be miserable even when all the material and social conditions for happiness have been met. During the normal course of events, your mind will determine the quality of your life.“
— Sam Harris American author, philosopher and neuroscientist 1967
Source: 2010s, Waking Up (2014), p. 204
„Those who are not looking for happiness are the most likely to find it, because those who are searching forget that the surest way to be happy is to seek happiness for others.“
— Martin Luther King, Jr. American clergyman, activist, and leader in the American Civil Rights Movement 1929 - 1968
— Chinmayananda Saraswati Indian spiritual teacher 1916 - 1993
Quotations from Gurudev’s teachings, Chinmya Mission Chicago