Hundreds of years ago, John Selden noted, "Ignorance of the law excuses no man; not that all men know the law, but because 'tis an excuse every man will plead and no man can tell how to confute him." We can't confute (that is conclusively refute) Selden's argument, so instead—with no excuses!—we present some laws no one can afford to ignore.
Forget the mathematical and scientific laws cluttering the books: today we go beyond thermodynamics and look at the story behind Murphy's Law. The way the story goes, the original Murphy was an engineer working on an Air Force project in the late 1940s. Supposedly, out of 16 possible errors on one aspect of the project, 16 were made. Impressed, the philosophical engineer Murphy mused, "If there are two or more ways to do something, and one of those ways will result in a catastrophe, then someone will do it."

Over the years, Murphy's words were amended to, "Anything that can go wrong, will." The popularity of Murphy's Law spawned plenty of successors and corollaries, including the Extended Murphy's Law ("If a series of events can go wrong, it will do so in the worst possible sequence"), and our favorite, Considine's Law ("Whenever one word or letter can change the entire meaning of a sentence, the probability of an error being made will be in direct proportion to the embarrassment it will cause").

Our production and research support comes from Merriam-Webster, publisher of language reference books and CDs including Merriam-Webster's Dictionary of Law.

What about Parkinson's Law: "Work expands to fill the time avalable for its completion".

Parkinson's Law:

General recognition of this fact is shown in the proverbial phrase 'It is the busiest man who has time to spare.' Thus, an elderly lady of leisure can spend the entire day in writing and dispatching a postcard to her niece at Bognor Regis. An hour will be spent finding the postcard, another in hunting for spectacles, half an hour in a search for the address, an hour and a quarter in composition, and twenty minutes in deciding whether or not to take an umbrella when going to the pillar box in the next street. The total effort that would occupy a busy man for three minutes all told may in this fashion leave another person prostrate after a day of doubt, anxiety, and toil.