In plain words
Nowhere in all of creation can one find another treatise like the Manu Dharma Śāstra. In what age, by whom, could such a treatise ever be composed? Neither Hindu doctrines nor scriptures submit themselves to physical science. Physical scientific knowledge keeps advancing day by day, but it keeps raising new doctrines that refute yesterday's. If that is so, how could eternal truths -- scriptural doctrines -- ever be tested by physical science? Today's scientists hold that, without relying on blind belief, they are investigating every matter merely by putting it to the test and examining it scientifically. They delude themselves into calling all this 'independent inquiry.' This is not the truth. We have no need to raise some new doctrine; everything has already been established. Our only duty is to grasp it.
The matters investigated by Western philosophers from Kant down to Spencer are mere fragments of the doctrines of dvaita, advaita, and viśiṣṭādvaita. The Hindus had already investigated and systematized all these matters long before. The Vedic religion and the Hindu religion rest on the observances of varṇa and āśrama. But the subject of varṇa in religion, and the term Māyā in Vedānta, are commonly met with neglect and weariness, and are subjected to both rejection and criticism. Some conclude that the distinctions of varṇa are man-made, and that to call this world, which is directly visible and experienced, Māyā is sheer folly; and they go on criticising.
When it happens that the Smṛti verse 'The fourfold order was created by Me, by the division of guṇa and karma' and the Śruti verse 'The brāhmaṇa was His mouth, His arms the kṣatriya' are taken to indicate a division of varṇa made by the Supreme Lord, their meaning and purport end up being construed in an altogether different way. So, whether varṇas actually