Philosophy of Taxation

Let's say I can earn $100 tending the lawn of a neighbor. Upon receipt of this money, I have to pay the government a third as taxes.

What is the theory of this taxation?

• Am I paying them for the right to work?
• Am I taxed for the right to live in the country (presumably they hold it together, rather than the actions of the citizens)?
• Am I settling debt in advance for implied consumption of government services, though this work involves only my own labor?
• Am I compensating the government for costs incurred, for example, their invaluable help in making grass grow and leaves fall?
• Are taxes a fee on having a working currency, though they desire to tax barter exchanges also and often ban alternative currencies?

Government would be better if it explained its purpose and costs instead of merely presenting bills that must be paid, imposed by force.