For example, in one yoga-siddhi there is development of the power to become so light that one can float in the air or on water. That is also being performed by modern scientists. They are flying in the air, they are floating on the surface of the water, and they are traveling under the water.
After comparing all these mystic yoga-siddhis to materialistic perfections, we find that the materialistic scientists try for the same perfections. So actually there is no difference between mystic perfection and materialistic perfection. A German scholar once said that the so-called yoga perfections had already been achieved by the modern scientists, and so he was not concerned with them. He intelligently went to India to learn how he could understand his eternal relationship with the Supreme Lord by means of bhakti-yoga, devotional service.