In Hinduism, the terms Purusha and Prakriti are often used during spiritual discourses to understand the eternal truth. Purusha is the consciousness (sat roopam) or mindfulness which is beyond time, space and cognition while the Prakriti is matter or material. Therefore, every individual/living being (Jiva) consists of both the Purusha and the Prakriti, wherein its mind is the Purusha while its body is the Prakriti.
As per the Vendanta, there are three aspects – the Satya, Asatya and the Mithya. The Satya refers to the one which exists but doesn’t change; Asatya is the one that doesn’t exist, and the Mithya is that which exists but keeps changing. Therefore, the mind (Purusha) remains static, while everything that we feel consume through our sense organs (Prakriti) keeps changing. Hence, it would not be wrong to say that Purusha is eternal, but Prakriti isn’t.
But who is Adi Purush?
The Universe (Jagat) doesn’t exist on its own. There is some supernatural power that governs and rules it. Therefore, it is the Ishwara, who is the Saguna Nirakara (meaning the one who is formless yet with attributes). It is the Ishwara that created Lord Brahma, who in turn created the Universe.
From the perspective of Bhagavatam, Lord Brahma appeared from the navel of Lord Vishnu, who is hailed as the Ishwara. Therefore, followers of the Vaishnava sect believe that Lord Vishnu is the Ishwara or the Sarva Shaktimaan (the most powerful) and the Sarvagna (the one who knows everything). However, the followers of the Shaivite sect, believe that it is Lord Shiva, who is the Ishwara.
To make worship relatable, the Ishwara takes akara or forms.
Interestingly, Lord Shiva and Lord Vishnu worship each other. Once, Goddess Parvati wondered who does Lord Shiva worship, as she believed that he is the supreme power. Lord Shiva answered Parvati’s question by saying that he meditates upon Lord Vishnu. And Lord Vishnu worships Lord Shiva as the supreme power. A classic example of this belief is the Rameshwaram temple, a shrine dedicated to the Shiva Linga made and worshipped by none other than Lord Rama himself. And who was Lord Rama? He was the seventh incarnation of Lord Vishnu. Even in the Dwapar Yuga, Lord Vishnu worshipped Lord Shiva.
Therefore, Adi Purush is the Ishwara, who is either referred to as Lord Shiva or Vishnu. Lord Brahma can also be hailed as the Adi Purush if one were to take it in the literal sense, where Adi means ‘first’, and Purush means ‘man’. Since Lord Brahma was the first one to be created, he can also be addressed as Adi Purush.