Concept
Tranquillity

Overview
Tranquillity (also spelled tranquility) is the quality or state of being tranquil; that is, calm, serene, and worry-free. The word tranquillity appears in numerous texts ranging from the religious writings of Buddhism—where the term passaddhi refers to tranquillity of the body, thoughts, and consciousness on the path to enlightenment—to an assortment of policy and planning guidance documents, where interpretation of the word is typically linked to engagement with the natural environment. It is also famously used in the Preamble to the United States Constitution, which describes one of the purposes for which the document was establishing the government as to "insure domestic Tranquility".
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
In the original texts
Passages from public-domain books where Tranquillity is discussed.
Of the same class of virtues with courage is that undisturbed philosophical tranquillity, superior to pain, sorrow, anxiety, and each assault of adverse fortune. Conscious of his own virtue, say the philosophers, the sage elevates himself above every accident of life; and securely placed in the temple of wisdom, looks down on inferior mortals engaged in pursuit of honours, riches, reputation, and every frivolous…
David Hume, An Enquiry Concerning the Principles of Morals
names the idea; opens on it
The most extensive public benevolence which can commonly be exerted with any considerable effect, is that of the statesmen, who project and form alliances among neighbouring or not very distant nations, for the preservation either of, what is called, the balance of power, or of the general peace and tranquillity of the states within the circle of their negotiations. The statesmen, however, who plan and execute such…
Adam Smith, The Essays of Adam Smith
states what it is; names the idea; opens on it
What do they gain, if the very tranquillity they enjoy is one of their miseries? Tranquillity is found also in dungeons; but is that enough to make them desirable places to live in? The Greeks imprisoned in the cave of the Cyclops lived there very tranquilly, while they were awaiting their turn to be devoured.
Jean-Jacques Rousseau, The social contract & discourses
states what it is; names the idea
Peace and tranquillity are not merely the absence of open friction and disorder. They mean specific, easily-known, and generally recognized principles which determine the province and limits of the legitimate activity of every person.
John Dewey, Ethics
commentary markers; states what it is; opens on it; names the idea
But great numbers of mankind have been satisfied with much less. The main constituents of a satisfied life appear to be two, either of which by itself is often found sufficient for the purpose: tranquillity, and excitement. With much tranquillity, many find that they can be content with very little pleasure: with much excitement, many can reconcile themselves to a considerable quantity of pain. There is assuredly no…
John Stuart Mill, Utilitarianism
names the idea
Related ideas
Place in the tradition
Part of Philosophical pessimism.