Sanatan Dharma describes the entire manifest universe, including the human body, as built from five great elements: Prithvi (earth), Ap (water), Agni (fire), Vayu (air), and Akasha (space or ether). These are not merely physical substances in the modern chemical sense, but principles of density — Akasha is the subtlest, offering no resistance; each successive element adds a layer of resistance and form, down to Prithvi, the densest and most solid.
Each element is also associated with one of the five senses and their corresponding sense organs: Akasha with hearing, Vayu with touch, Agni with sight, Ap with taste, and Prithvi with smell. This is why Ayurveda, the traditional system of medicine rooted in the same worldview, diagnoses imbalance not in terms of germs or isolated symptoms, but in terms of which elements have become excessive or deficient in a person’s constitution.
The five elements are not unique to Sanatan Dharma — Buddhist, Jain, and even ancient Greek thought describe similar elemental systems — but the tradition’s particular contribution is to treat the Pancha Mahabhuta as a bridge between physics and consciousness: the same five elements that compose a mountain also compose a human body, which is why the microcosm of the body is said to mirror the macrocosm of the universe.