[slg]

You are ignoring a secondary reasons for taxes. The primary reason is obviously to raise funds for public use. The secondary reason is to give the government more control over the economy. You are right, there are ways to drastically simplify tax law if we wanted to tax ever dollar at the exact same rate or had very clear marginal tax rate buckets. We don't do that because we want to incentivize certain actions. On a personal level, you get a tax break if you pay for your education, you get a tax break if you invest in your career, you get a tax break if you have children, you get a tax break if you earn your money through investments rather than through employment, etc. We don't necessarily do those things to be nice. We do those things because we believe they are good for the overall economy and it is beneficial for them to be incentivized.

[hartator]

You can still do all of that with no corporate taxes. As every incentives you cited are on the individual taxes.

[slg]

Sorry, I thought it would be clear that I wasn't trying to cite a complete list. There are also countless corporate tax incentives too. Clean energy is one example. How do you incentivize companies to use clean energy by taxing individuals?