He firmly believed that unlimited expansion of commerce and industry, like we have seen in the last 150 years, would lead to to a class of wage laborers who rely on others to survive. They wouldn't be able to provide their own income or sustenance. These people would be vulnerable to political subjugation and economic manipulation. Jefferson wanted to combat this with an income tax that scales with a persons wealth. This would a disincentive to hoard wealth and provide some funds to distribute downward.
It may sound a bit like Communism, but Red Nations didn't exist back in the day when new government ideas were being formed. Jefferson was just trying to think of an economic structure that would create a strong, self-sustaining, financially secure people.
