In plain words
Buddhi means what is joined purely with the power of enquiry. It makes us recognise what is good and what is bad. The nature of such a Buddhi is, in some measure, the very form of Manas. Then there is citta. To think without ceasing is the very nature of citta. Then there is aham. That is, the Ātma. It is what fills every place. What arose from this is Ahaṅkāra. Ahaṅkāra means "I". It spreads this principle of "I" over the world. In sum, all four of these are nothing but shapes of Manas. When one and the same brāhmaṇa is cooking, we call him the cook brāhmaṇa. The brāhmaṇa who performs worship in temples we call the priest. Those who give teaching in the śāstras we call śāstrīs. A person of great learning they call a paṇḍit. Though their work, their thoughts and their natures appear different from one another, every one of them is a brāhmaṇa. In the same way, we must recognise the truth that though these words, Manas, Buddhi, citta and Ahaṅkāra, take many forms and pass through manyness, they are nothing but marks of the Ātma. We must enquire well into this: that this is the power of the mind. Vedānta said, "Mana eva manuṣyāṇāṃ kāraṇaṃ bandhamokṣayoḥ." For bondage and for freedom alike the mind alone is the support; this is true. Not only this. "Manomūlam idaṃ jagat." As the mind is, so does the man become. This is what they called "Yad bhāvaṃ tad bhavati." In English this is, "So think of the man and so is the man." Such a sacred principle has been proclaimed and spread equally in all countries.
Over this Manas, Buddhi, Ahaṅkāra and citta there is one master. Without it these four cannot live even for a moment. This is what they called Prajñā. We must understand the principle of this Prajñā well. They have gone on spreading it under many names, saying Prajñā means intellect, means cleverness, means discernment. This is not right. This Prajñā is only a passing Prajñā, not the lasting Prajñā. The form of Prajñā spoken of in Vedānta shines evenly in the body's cells, in Manas and in the Ātma. So this Prajñā has a certain kind of power. Only when we recognise this principle of Prajñā can we know "Prajñānaṃ Brahma." Between what is called Prajñā and what is called the Ātma, or what is called Brahman and Satya, there is no difference. That is why this is Constant Integrated Awareness. That is, it has settled evenly into everything; so such Prajñā is present in man. At a time when the man of today cannot know his own principle, his very humanness, how then can he recognise divinity? First of all we must try to recognise humanness rightly and well. Man is not an ordinary being. "Jantūnāṃ narajanma durlabham": among all these crores of living beings, humanness alone carries a special worth. We must try to know so strong and so special a principle.