In Laozi's philosophy, the number 3 holds great significance as it represents the balance and harmony of the universe. This is known as the principle of the "Three Treasures" or "Sanbao" in Chinese.

The first treasure is known as "compassion," which is represented by the virtue of kindness and love. This treasure emphasizes the importance of treating others with empathy and understanding, and to have a compassionate heart towards all living beings.

The second treasure is "frugality," which is represented by the virtue of simplicity and moderation. This treasure teaches us to live a simple and humble life, free from material desires and excess. By practicing frugality, we can achieve inner peace and contentment, and avoid the chaos and turmoil that comes with excessive desires.

The third treasure is "humility," which is represented by the virtue of modesty and selflessness. This treasure teaches us to let go of our ego and to be humble in our actions and thoughts. By being humble, we can avoid conflicts and live in harmony with others.

In addition to the Three Treasures, the number 3 also symbolizes the three main forces in the universe – Heaven, Earth, and Humanity. These forces are interconnected and work together to maintain balance and harmony in the world. This concept is known as the "Three Powers" or "Sancai" in Chinese.

Heaven represents the spiritual realm and is associated with the Tao, the ultimate reality in Taoism. Earth represents the physical world and is associated with nature and the cycles of life. Humanity represents the human aspect and is associated with moral values and the cultivation of virtues.

The number 3 also plays a significant role in the Taoist concept of yin and yang, which represents the balance of opposing forces in the universe. Yin and yang are often depicted as two halves of a circle, with the number 3 symbolizing the third, middle path that brings balance and harmony between the two.

Overall, the number 3 in Laozi's philosophy represents the balance and harmony of the universe, and the importance of living a simple, compassionate, and humble life. By understanding and embracing the Three Treasures and Three Powers, one can achieve inner peace and harmony with the world.