Idleness is expressed either as a fraction between 0 and 1, or a percentage between 0% and 100%. It represents the fraction or percentage of time that an individual or a society is inactive, doing nothing, at leisure.
Unit or perfect idleness is 100% or complete idleness. It is practically unachievable, because there is always some amount of work that needs to be done. Even if human technology were to become so developed that no humans produced any of the goods they used, humans would still have to monitor the performance of their automated tool systems to ensure they were working properly. And if they were to automate this monitoring, they would have to monitor the automated moitoring systems.
Zero idleness is the state where individuals or societies are working continuously, with no idle or leisure time. Zero idleness is the threshold of death for individuals, or extinction for societies, because if idleness falls further, then men are unable to perform enough work to maintain themselves in the available time. If it takes an entire day's work for a man to gather food to just maintain himself alive, then if more than an entire day's work is needed, then each day's work he does results in an accumulating shortfall of food, and starvation and death.
Real or actual human idleness can never rise above unit or perfect idleness, nor fall below zero idleness. Negative idleness indicates a circumstance where human life is unsustainable, where a man must work for more than one day each day to maintain himself.
Negative idleness is used in Idle Theory sometimes to denote untooled human idleness - the effective idleness of humans who do not have any useful, idleness-increasing tools - to demonstrate that it is only by making and trading and using such tools that human life can keep its head above water - above zero idleness -, and that without tools they would perish.
In some cases the idleness of individuals is calculated to be greater than 100% idleness. Since real human idleness can never rise above 100%, a calculated idleness of 300% can mean either that a man is (almost) 100% idle, and in addition has 2 men working for him continuously, or that he is 50% idle and has 2.5 men working continuously for him. Since his idleness cannot be increased, the men working for him cannot be performing idleness-increasing work for him, but are (most likely) providing him with luxuries and amusements.
The value of a tool is the amount of time that it saves an individual over its lifetime. If the use of a knife in gathering plants saves a man 1 hour a day, and the tool's lifetime is 12 days, the value of the tool is 12 hours.
The same tool may have different values depending on the use to which it is put.
The cost of a tool is the amount of time required to make it.
The price of a tool is the amount of money that is paid to buy a tool. Since tool values and costs are measured in human time, the real price of goods is also measured in human time. In Idle Theory's economic simulations, money takes the form of a IOU which is a promise to perform some amount of work.
Tool prices can also be denminated in terms of other tools.
A useful tool is one which overall saves men time in some activity in which they are necessarily engaged. A tool is a useful tool if the value of the tool exceeds its cost, because the time gained from using the tool exceeds the cost of making it. Useful tools act to increase human idleness.
Luxuries are tools whose cost exceeds their value. The use of luxuries acts to decrease human idleness.
Luxuries may simply be badly made tools, such as blunt knife which saves its owner little time, or one which becomes blunt very quickly, while taking a long time to make. Equally a knife that is both sharp and durable, but has a pearl handle and an ornamentally engraved blade may have cost so much to produce that its real value is less than its cost.
Most luxuries, however, are goods that are desired for themselves, or for the pleasure and amusement they provide, and not for any idleness-increasing utility. Works of art - paintings, sculptures - have a cost of production, but have no value as tools. If luxuries actively use up time, then their value is negative. A book which requires its owner to read it, or a theatre play which requires the audience to watch it, or a game of chess that requires people to play it, may all be regarded as having negative values. Incapacitating drugs, or games or pastimes which carry a threat of physical injury (mountaineerig, rugby, etc) may also be regarded as having negative value.
When human life is largely idle, it is natural that people should consider ways in which to while away their idle time. Were human life by nature one of perfect idleness, there could be no useful tools, because idleness could be increased no further. In such a society, the only goods that could be manufactured and traded would be luxuries of one sort or other.
Since the real value and cost of tools and luxuries is measured in human time, their real price is also measured in human time. In the Idle Theory economic simulation model, real pricing is used, in the form of money which is a promise to perform some amount of work. If the price of some good is 2 days, then a buyer can be regarded as handing the seller an IOU on which he promises to perform 2 days work on request. If these IOUs say that "Mr. X promises to perform N hours of work on request for Mr. Y", then these IOUs cannot circulate as currency. If the promise is that "Mr. X promises to perform N hours of work on request for whoever bears this promise," then these can be used as currency, because if the notes become interchangeable.
This form of money only works if everyone keeps their promises, and they don't issue more IOUs than they can pay. It is quite possible for a tool to be used as money, and for people to pay for goods with some number of small tools. Potential buyers of tools must then acquire these tools before they can buy anything. This restricts the potential for abuse. However, since the maker of whichever tool is used as money is effectively the owner of a mint, he also can flood the trading system with money. Equally, if there is not sufficient money in circulation in the system, trading may be hampered.
Commodity money of this sort has a source - its manufacturer - and a sink - its buyers and users -. The sink ensures that as money is entering the trading sysem, it is also being removed. Historically, gold and silver ingots or coins have been used as money, and both are useful metals. Gold, in particular, does not easily corrode, and so gold can be used as money for long periods in ways that, say, potatoes cannot. Gold and silver are also divisible into small units so that the price of most goods can be denoted by them. The historic problem with the use of gold as money has been that there has frequently not been enough in circulation to cover transactions. This led to the introduction of banknotes which were redeemable in gold, and ultimately, when these notes were seldom redeemed, to the issue of banknotes which were not redeemable in gold.