In plain words
What science has learnt today is very little. But the men of today pride themselves that they have learnt an atom's worth of knowledge. But spirituality teaches that the vast is in the atom itself. 'Aṇoraṇīyān mahato mahīyān': it is the atom within the atom and the vast within the vast. When we put a small seed in the earth and plant it, it grows into a great banyan tree. Where did so big a tree come from? It came from that small seed itself. In that small seed itself the branches and twigs, the leaves and flowers, all are held within it. But when do they come forth outside? Only when this seed lets its own shape fall apart does that tree come out. When the seed is planted in the earth it burns its own form to ash. That is, it gives up its Ahaṅkāra. It gives up its own shape. Only then does it take on a new shape. If its shape stays just as a shape, we cannot understand at all the infinity that is the new shape. Even in so infinite a tree there is a seed the size of an atom. So, 'aṇoraṇīyān mahato mahīyān': the infinite comes from the atom. The atom comes from the infinite. So when we enquire into these two, the infinite and the atom, both are one. But this one's shape is this, that one's shape is that. The difference of shapes and their changes is its only measure, but the substance is one; this is the chief secret of the Upaniṣads.
Each Upaniṣad has set out well the secret of creation. Those who understood them have each understood them according to their own intelligence and their own power of mind. That comes from their own natural habits. These are natural changes. When a meat-eater goes into the forest and sees a bird on a tree, ah! If I strike this, all at home can eat it. So he keeps only its flesh in view. But when a poet sees it, ah! How fine its colours are, how soft its feathers are; so he goes on describing it beautifully. Though the thing is one, each one's sight is different. In the same way, where did this fault of sight begin? It began from natural habits.