The preamble of a constitution is a brief introductory statement that outlines the fundamental purposes, values, and principles upon which the rest of the constitution is built. While not legally binding in itself, the preamble serves as a guiding framework and sets the tone for the interpretation and application of the constitution's provisions.

The philosophical key of the constitution refers to the underlying philosophy or ideology that is expressed or implied within the preamble. It represents the fundamental ideas and aspirations that shaped the drafting of the constitution and provides a vision for the society and government it seeks to establish.

The Explanation Of The Philosophical Key Of A Constitution Is In Its Preamble Are:

1. Sovereignty and Power:
   The preamble may emphasize the source of power and authority within the constitution. It can assert the sovereignty of the people, highlighting that the government derives its power from the consent of the governed.
    
2. Social Contract:
   The preamble may reflect the concept of a social contract, which implies an agreement between the people and the government. It can express the idea that the government exists to protect the rights and promote the welfare of its citizens.
    
3. Equality and Justice:
   The preamble may emphasize principles of equality, justice, and fairness. It can advocate for the establishment of a society where all individuals are treated equally under the law and have access to justice.
    
4. Liberty and Freedom:
   The preamble may underscore the importance of individual liberties and freedoms. It can express a commitment to protecting and preserving the rights of citizens, such as freedom of speech, religion, and expression.
    
5. Democracy and Participation:
   The preamble may highlight the value of democratic principles and citizen participation. It can emphasize the importance of popular sovereignty, representative government, and the right of citizens to participate in the political process.
    
6. National Identity and Objectives:
   The preamble may articulate the core values, aspirations, and objectives of the nation.

It has been achieved in following dimensions:

• Sovereign:
  It emphasizes the sovereignty of the Indian people, indicating that power rests with the citizens
   
• Socialist:
  It signifies the commitment to a socialist society, aiming for social and economic equality and justice.
   
• Secular:
  It enshrines the principle of secularism, ensuring equal treatment of all religions by the state and promoting religious harmony.
   
• Democratic:
  It highlights India's commitment to democracy, with the people having the power to elect their representatives and participate in decision-making.
   
• Republic:
  It establishes India as a republic, where the head of state is an elected individual, rather than a hereditary monarch.
   
• Justice:
  It emphasizes the importance of justice, including social, economic, and political justice for all citizens.
   
• Liberty:
  It guarantees individual liberties and freedoms, ensuring that every citizen enjoys personal freedom within the boundaries of the law.
   
• Equality:
  It promotes equality of status and opportunity, prohibiting discrimination based on caste, religion, race, gender, or place of birth.
   
• Fraternity:
  It aims to foster a spirit of brotherhood and a sense of unity among all citizens, transcending barriers of religion, language, or region.

Conclusion:
In summary, the preamble serves as an introductory statement that outlines the fundamental purposes, values, and principles of the constitution. It reflects the source of power, social contract, principles of equality and justice, individual liberties and freedom, democratic principles, and the nation's identity and objectives.