As I mentioned in the post, we are fortunate to live at a time when science has made enough progress to explain some of these issues. I will be addressing some of these issues in detail in upcoming posts.
To answer your question, Einstein pointed out that energy and matter are the same things. His famous equation, E = mc^2, quantifies the relationship between energy (E), and the mass (m), and c is the speed of light. Here “mass” (m) can be called the amount of matter (or the “weight” as we normally call it).
Our mental body (manomaya kaya or gandhabba) is created by the energy emitted by our thoughts while doing a very strong kamma. As I explained there, this energy is VERY VERY small, and the “mass” of the gandhabba is VERY VERY small (it is billion times smaller than an atom in modern science).
In other words, the energy in our thoughts can create matter, of course VERY VERY small amounts of matter.
– This gives an indication of how fine the “body” of a gandhabba is!
So, this kammic energy is real.
Please feel free to ask questions. I am a physicist, so I may be taking too much for granted. I will do my best to simplify things. I just don’t know how much to simplify.