I see taxation as a moral problem: how much of my money is the state entitled to?
Does it all belong to the state? If so, then we throw property rights out the window (the ancient economic foundations of society), along with the market economy, one of the great bastions of human progress.
Does none of it belong to the state? If so, then an individual is entitled to keep all the wealth they have produced. Many would remark it is hard to fund a government on voluntary donations: taxation must be compulsory or the government would not get financed, and would struggle to fulfill its function (defending life, liberty, and property rights). Of course, this is another serious moral issue: if people are unwilling to pay for something, who determines whether they should be forced to pay for it? Who determines what they should be forced to pay for? There is a whole multitude of questions that should come up in the minds of us, the governed.
Most people accept compulsory taxation as a necessary evil, some even as a public good (thanks, Keynes). The result is that there is some popularly-accepted middle ground in most countries these days: the government is entitled to some amount of one’s wealth. Another question arises: what is this amount? How is this amount determined? How much is too little? How much is too much?