Vaisheshika is one of the six major schools of Hindu philosophy, founded by the sage Kanada around the 2nd century BCE. It is based on the concept of atomistic realism, which holds that the universe is made up of indivisible, eternal, and indestructible particles called atoms.

According to Vaisheshika, these atoms are the fundamental building blocks of all matter and everything in the universe is composed of them. These atoms are categorized into nine types based on their qualities and characteristics, such as color, taste, smell, and touch. This classification system is known as dravya or substance.

The Vaisheshika school also believes in the existence of an ultimate reality, known as Brahman, which is the source of all existence. However, unlike other schools of Hindu philosophy, Vaisheshika does not see Brahman as a personal deity, but rather as an impersonal force that governs the universe.

One of the key principles of Vaisheshika is the concept of causality, known as karma. According to this principle, every action has a corresponding reaction, and this cycle of cause and effect governs the universe. This belief in karma is closely tied to the concept of reincarnation, where the soul is believed to be reborn into different bodies based on its accumulated karma.

In addition to its focus on the physical world, Vaisheshika also delves into metaphysical concepts such as time, space, and consciousness. It sees time as a continuous flow of moments and space as an infinite, three-dimensional expanse. Consciousness, on the other hand, is seen as a separate entity from the body, and it is believed to be eternal and indestructible.

Overall, Vaisheshika provides a comprehensive understanding of the nature of reality, emphasizing the role of atoms and causality in shaping the universe. Its principles have greatly influenced other schools of Hindu philosophy, as well as scientific thought in India.