Progressive Tax System
A progressive tax system is a method of taxation where individuals with higher incomes are required to pay a higher percentage of their income in taxes compared to those with lower incomes. This means that as income increases, the tax rate also increases, resulting in a higher overall tax burden for individuals with higher incomes.

Explanation:
The progressive tax system aims to achieve greater income equality by redistributing wealth from those who have more to those who have less. It is based on the principle of ability to pay, where individuals who earn more have a greater ability to contribute to the tax system.

Key Points:
1. Graduated Tax Rates: In a progressive tax system, tax rates are typically structured in a graduated manner, with different income brackets and corresponding tax rates. As income increases, the tax rate also increases progressively.

2. Marginal Tax Rate: The term "marginal tax rate" refers to the tax rate applied to the last dollar earned. In a progressive tax system, the marginal tax rate is higher for individuals with higher incomes. This means that as individuals earn more, the additional income is taxed at a higher rate.

3. Redistributive Effect: The progressive tax system is designed to promote income redistribution by taking a larger share of income from those at the top of the income distribution and providing more benefits and services to those at the lower end. This helps to reduce income inequality in society.

4. Social Welfare Programs: The revenue generated from progressive taxation is often used to fund social welfare programs such as healthcare, education, and social security, which primarily benefit lower-income individuals and families.

5. Criticisms and Challenges: While the progressive tax system is intended to promote fairness and equality, it is not without criticism. Some argue that high tax rates on the wealthy can discourage investment and economic growth. Additionally, there may be challenges in accurately defining income brackets and determining appropriate tax rates.

Conclusion:
The progressive tax system is characterized by higher-income individuals paying a higher percentage of their income in taxes. This system aims to promote income equality and fund social welfare programs. However, it is not without criticisms and challenges.