|A Jun 1776 draft copy of The Declaration of Independence, by Thomas Jefferson, wherein the phrase: “life, liberty, and property” is changed to “life, liberty and the pursuit of happiness” as the three unalienable rights of humans.|
Pursuit of happiness
On 29 Nov 1775, American thinker Thomas Jefferson wrote the following to John Randolph: 
“Believe me, dear Sir: there is not in the British empire a man who more cordially loves a union with Great Britain than I do. But, by the God that made me, I will cease to exist before I yield to a connection on such terms as the British Parliament propose; and in this, I think I speak the sentiments of America.”
In Jun 1776, Jefferson began drafting Declaration of Independence, a formal announcement of the detachment of the thirteen newly independent American states from the British Empire, in which he originally penned the phrase “life, liberty, and property” as the three "unalienable rights" that humans need to exist. (Ѻ) He later edited, shown adjacent, it to read “life, liberty and the pursuit of happiness”, which has since become one of the most famous statements in American government documentation:
This change, baring prolonged discussion, may have reflected certain aspects of Jefferson's Epicurean belief system.
Ostwald happiness formula
See main: Ostwald happiness formulaIn 1905, German physical chemist Wilhelm Ostwald penned a happiness equation based on his energetics theories.  Ostwald's happiness equation reads as follows:
where G is Gluck (happiness), A is Arbeit (work or ‘energy expended in doing useful work’), W is Widerstand (energy dissipated in overcoming resistance), and k supposedly some type of proportionality constant. 
Porteus’ theory of happiness
See main: Porteus' theory of happinessIn 1987, American philosopher Elizabeth Porteus, daughter of the James Dole the “Pineapple King” of Hawaii, her My Twentieth Century Philosophy, discuss a connection between thermodynamics, happiness, and impulses.
Porteus outlined the view that since, according to generalized colloquial point of view, the second law of thermodynamics is a “law of disintegration”, meaning that “complicated arrangements always break down into less complicated ones”, a state of life happiness would occur when one aligns themselves with the force or “impulse of integration” in unison with the current of creation or growth of structure and form as seen in evolution.  By “creative”, Porteus refers to not only what is commonly considered creative such as "painting pictures, making music, writing books, making pottery or making any kind", but also to "any impulse to create a new integrated arrangement of the elements of reality." 
The following are related quotes:
“We see many who are struggling against adversity who are happy, and more although abounding in wealth, who are wretched.”— Publius Tacitus (c.100)
1. Merriam-Webster’s Collegiate Dictionary, 2000.
2. (a) Dole, Elizabeth P. (2005). “Life, the Second Law of Thermodynamics, and Happiness”, Journal of Human Thermodynamics, Vol. 1, Issue 3. (pg. 21-26). October. Chicago: Institute of Human Thermodynamics.
(b) Porteus, Elizabeth, D. (1987). My Twentieth Century Philosophy. New York: Carlton Press, Inc.
3. Porteus, Elizabeth P. (1999). The Porteus Philosophy of Life: The Secret of Happiness (Nov. 14). Hawaii: Porteus Family Publishing.
4. Thims, Libb. (2007). Human Chemistry (Volume Two), (preview), (ch. 13: "Human Chemical Bonding", pgs. 515-560). Morrisville, NC: LuLu.
5. Data: When two American psychologists studied hundreds of students and focused on the top 10% "very happy" people, they found they spent the least time alone and the most time socializing. (Source: Wade, Dorothy. (2005). So what do you have to do to find Happiness? The Sunday Times Magazine, Oct. 02.).
6. (a) Ostwald, Wilhelm. (1905). “A Theory of Happiness”, International Quarterly, 11:316-26.
(b) Szabadvary, Ferenc. (1965). “Wilhelm Ostwald’s Happiness Formula”, Journal of Chemical Education, 42(12):678.
7. Hazelton, John H. (1906). The Declaration of Independence: Its History (pg. 19) (Ѻ). Da Capo Press, 1970.
8. Fleck, George. (1993). “1909 Nobel Laureate: Wilhelm Ostwald, 1853-1932”, in: Nobel Laureates in Chemistry, 1901-1992 (editor: Laylin James) (pgs. 61-66, esp. pg. 66). Chemical Heritage Foundation.
● Happiness – Wikipedia.