The two theories of special and general relativity clearly show the relationship between space, time, energy, and matter. Special relativity has shown that energy and matter are equivalent; energy can be converted into matter, and matter into energy. Again, general relativity shows that space, time, and matter are so interrelated that there cannot be any space-time without matter; similarly, there cannot be any matter without soace-time.
Since there cannot be any space-time without matter, and since there can neither be any matter without soace-time, therefore it can be asserted that space-time and matter have originated from one single source only. If the source of space-time and the source of matter were different, then there could not be such an interrelation between space-time and matter. Again, since energy and matter are identical, therefore we can assert that space, time, energy, and matter have originated from one single source only.
This interrelation between space-time and matter shows us that at the root of all things is the One, and that One is neither space, nor time, nor energy, nor matter, though space, time, energy, and matter have originated from that One only. If that One is neither space, nor time, nor energy, nor matter, then what is that One? It is not possible for anyone to say anything about that One, which is why Indian philosophy has only said neti, neti about that One; it is not this, it is not that, etc.