Sod's law is a name for the axiom of "bad fortune will be tailored to the individual" and "anything that can go wrong, will". "Toast will always land butter side down" is often given as an example of Sod's law in action. The phrase is seemingly derived, at least in part, from the colloquialism an "unlucky sod"; a term for someone who has had some bad unlucky experience, and is usually used as a sympathetic reference to the person.
Sod's law is similar to, but broader than, Murphy's law ("Whatever can go wrong, will go wrong"). For example, concepts such as "bad fortune will be tailored to the individual" and "good fortune will occur in spite of the individual's actions" are sometimes given as examples of Sod's law in action. This would broaden Sod's law to a general sense of being "mocked by fate". In these aspects it is similar to some definitions of irony, particularly the irony of fate. Murphy's technological origin on John Stapp's Project MX981 is more upbeat—it was a reminder to the engineers and team members to be cautious and make sure everything was accounted for, to let no stone be left unturned—not an acceptance of an uncaring uninfluenceable fate.
Some examples of "bad fortune will be tailored to the individual" include:
- Ludwig van Beethoven's loss of hearing—loss of hearing is bad fortune for anyone, but it is Sod's law that it would happen to a brilliant composer.
- Adolph Coors III, who was allergic to beer, was the heir to the Coors beer empire—being allergic to beer is bad fortune for many, but it is Sod's law that someone allergic to beer would inherit a beer empire (and, due to a botched kidnapping attempt, die because of the empire's wealth, thus being killed by beer, if only indirectly).
- Lou Gehrig developed amyotrophic lateral sclerosis (ALS), a paralyzing neurological disorder, but it is Sod's law that this would happen to an athlete. ALS is commonly called "Lou Gehrig's disease" in the United States.
Some examples of "good fortune will occur in spite of the individual's actions" include:
- If you take your raincoat and umbrella with you, it will be sunny—any attempt you make to control your destiny (in this case how wet you get) will be thwarted by fate. This example is actually a case of Sod's Law applying both in this sense and the one defined by Murphy's Law, since the act of either carrying or having to wear the raincoat on a sunny day will very likely make you sweat, making you wet anyway.
- You move to another city, only to meet and fall in love with someone from your home town.
- Sod's First Law
- When a person attempts a task, he or she will be thwarted in that task by the unconscious intervention of some other presence (animate or inanimate)
- Task Completion Theorem: Nevertheless, some tasks are completed, since the intervening presence is itself attempting a task and is, of course, subject to interference.
- Sod's Second Law
- Sooner or later, the worst possible set of circumstances is bound to occur one way or another, it also reflects with Newton's Third law of motion i.e. for every action there is an equal reaction in opposite direction.
- Corollary: Any system must be designed to withstand the worst possible set of circumstances.
- Sod's Other Law
- The degree of failure is in direct proportion to the effort expended and to the need for success.