Public policy concerns the body of principles that underpin the operation of legal systems in each state. This addresses the social, moral and economic values that tie a society together: values that vary in different cultures and change over time. Law regulates behaviour either to reinforce existing social expectations or to encourage constructive change, and laws are most likely to be effective when they are consistent with the most generally accepted societal norms and reflect the collective morality of the society.
The Dictionary of Legal Quotations (1904) 
- Quotes reported in James William Norton-Kyshe, The Dictionary of Legal Quotations (1904), p. 212-213.
- It is impossible to say what the opinion of a man or a Judge might be as to what public policy is.
- Jessel, M.R., Besant v. Wood (1879), L. R. 12 C. D. 620.
- Public policy is a very unruly horse, and when once you get astride it you never know where it will carry you.
- Burrough, J., Richardson v. Mellish (1824), 2 Bing. 252; quoted by Lord Bramwell in Mogul Steamship Co.;. McGregor, Gow and others, 66 L. T. Rep. 6.
- Public policy is a high horse to mount, and is difficult to ride when you have mounted it.
- A. L. Smith, M.R., The Driefontein Consolidated Mines, Ltd. v. Janson (1901), Times L. R., Vol. XVII., 605.
- Public policy does not admit of definition and is not easily explained. It is a variable quantity; it must vary and does vary with the habits, capacities, and opportunities of the public.
- Kekewich, J., Davies v. Davies (1887), L. R. 36 C. D. 364; see also Egerton v. Earl Brownlow, 4 H. L. C. 1.
- The great end, for which men enter into society, was to preserve their property. That right is preserved sacred and incommunicable in all instances, where it has not been taken away or abridged by some public law for the good of the whole. . . . Distresses, executions, forfeitures, taxes, &c, are all of this description; wherein every man, by common consent gives up that right, for the sake of justice and general good.
- Lord Camden, Entick v. Carrington (1765), 19 How. St. Tr. 1066.
- There are many cases in which individuals sustain an injury, for which the law gives no action; for instance, pulling down houses, or raising bulwarks for the preservation and defence of the kingdom against the King's enemies.
- Butter, J., Governor, &c. of Cast Plate Manufacturers v. Meredith (1792), 4 T. R. 797.
- The principle of public policy is this: ex dolo malo non oritur actio. No Court will lend its aid to a man who founds his cause of action upon an immoral or illegal act.
- Lord Mansfield, Holman v. Johnson (1775), Cowp. 343.
- The argument of public policy leads you from sound law, and is never argued but when all other points fail.
- Burrough, J., Richardson v. Mellish (1824), 2 Bing. 252.
- Whatever is injurious to the interests of the public is void, on the grounds of public policy.
- Tindal, C.J., Horner v. Graves (1831), 7 Bing. 743.