Vedic thought holds that the best instrument of knowledge is the silent brain. This allows the brain itself, like an unflawed mirror, to directly reflect reality inside oneself. The mind becomes a reliable instrument of direct knowledge beyond the limitations of the senses. This silent mind is clearly defined in the Yoga Sutras of Patanjali and other texts as the state of samadhi.
When the brain is in a state of peace and balance it becomes capable of directly perceiving the nature of things, which is consciousness and bliss. This is samadhi- pramana, samadhi as a means of knowledge in yogic thought, which opens up the inner world of the mind as clearly as our eyes open up the outer world of the senses.
In Vedic science, the meditative mind in samadhi is regarded as the appropriate instrument for knowing the inner reality. Pure consciousness, God or Brahman, after all, is beyond name, form, number, time, place and person or it would just be another object or entity in the outer world. That which comprises the totality but is not limited by the totality cannot be examined by the instruments that work to provide knowledge of limited things.
This does not mean that examining the brain waves of meditators and other scientific experiments of this order are not of any value but that these are secondary and indirect means of knowing the internal reality, like trying to examine a person through their body as reflected in a mirror, rather than examining the body directly.
We must employ the right instrument of knowledge to gain adequate knowledge something. One cannot see the Sun with one’s hears, for example. Only the eyes will reveal the light of the Sun. Similarly, the appropriate instrument for knowing the universal Being is not a limited instrument which looks externally, like a telescope, but the silent mind that is able to see within.
Yet while samadhi may not be ordinarily recognized means of knowledge in science, we must note that many great scientific discoveries have been made by scientists when they were in the reverie of the inspired, concentrated or peaceful mind, in a kind of samadhi. Those who do deep research or concentrating thinking also develop the mind in a yogic way that can fall into samadhi, even without knowing what the state is! One could argue that all great discoveries or inspirations arise in a samadhi-like state of absorption and concentration.
Yet samadhis cannot be taken without scrutiny either and, like any source of knowledge, they also can be limited, mixed or partial. They are of different types and lesser Samadhis may not yield entirely correct knowledge.