When Man acts, he attempts to satisfy his most urgent Needs first and then move on to satisfy the Need he considers next most urgent. In attempting this, he will try to expend as little of his resources as possible. He is however aiming at an uncertain future, so no method can be absolutely guaranteed to succeed. Acting Man uses specific means to attain specific ends. He has a theory about how each goal can be realised.
An error in his theory may result in failure and consequently, suffer a complete loss. In this case a new effort may be required, which may again fail. If this process continues indefinitely the individual will be completely impoverished. However, Acting Man normally learns, and will change his approach if he wishes to survive.
If an isolated individual (Robinson Crusoe), stranded on uninhabited island wishes to survive, he will either find a water supply or he will die. He may have to construct a bucket and rope, or dig a hole, or make a container to capture rain. He may need to try many methods, or enter a pool and drink. His methods will depend on his local resources and his ability. He will normally choose the method, which he considers most likely to succeed, which he expects will satisfy his most urgent need and exact the lowest cost. Once he has had enough to drink, he may move on to find some food, and again, he will attempt to satisfy this need in the most economical fashion, accepting the limitations of his circumstances and his theory about how to achieve his goal.
Robinson may have a highly desirable but less urgent goal but he will not aim at the less urgent goal if his failure to satisfy his more urgent goal would deny the more desirable goal.
If Robinson has longer term goals, beyond the next moment, he will not simply, drink some water and then find a banana, then stitch part of his clothes, then build a piece of his shelter, only to repeat the process indefinitely. If it is at all possible, Robinson will try to create some spare time by storing some water and food, so that he may now dedicate more continuous time to acquiring a better food supply, making better clothes or improving his shelter or meeting some other Need. He will economise, prioritise and save. The storage, or saving, or temporary over-production of certain goods, allows him to either meet other needs or develop other methods of meeting his existing needs more efficiently. Alternatively, he may forego a less urgent need to be more productive at meeting a more urgent need. For instance, he might sacrifice repairing clothes, to make a container, which will allow him to temporarily store water. This saving might allow him to economise in trips to his nearest water source and spend the time on another Need. His goal is generally to utilise the method which involves the least expenditure of his resources which will also maximise his gains.
As Robinson satisfies his most urgent needs, he will turn his attention less immediate needs, to clothing, shelter, rest, leisure or whatever he chooses. He may become more expert in water collection and storage, finding food, and storing it and organising shelter etc., by transforming his environment. If his ability to meet his most urgent needs is successful, he will become richer. Those products will be more abundant or less scarce. His rate of production of goods to meet his basic needs may be more rapid than his rate of consumption. He will probably not continue to over-produce such goods and will use his over-production to meet a lower priority Need. His over-production is a saving, which means he doesn’t need to engage in that for a period and allows him to use his time on some other activity. These goods that meet less urgent needs often require more sophisticated methods of production.
While Robinson rests, he will be consuming his saved resources, his wealth. This may be shelter, food, water or other commodity. His resources will become depleted if he fails to replenish them. Robinson becomes wealthier by reducing scarcity. If he fails to produce enough or spends too much time resting, he will consume his savings and will suffer shortages of urgently needed, basic necessities. In Crusoe’s world, his objective wealth is his distance from disaster. If he can survive a month without needing to produce water, food or shelter, this is wealthier than needing to produce such resources tomorrow.
Even if Robinson really wanted to go hang gliding, if Robinson’s immediate goal is his survival, it would make no sense for Robinson to try to do this if he simultaneously desperately needed water. Devoting time to satisfying a less urgent Need before an urgent Need is inconsistent with the reality of human existence. It may be difficult for us to imagine ranking the multiplicity of our choices, but our actions always reveal our individual highest preference at the exact moment of the action.