Mind is not gross at all. The subtle mind constantly takes imprints of the world objects, employing the senses for the purpose. As is the mind subtle, so too are the imprints on it. Any reference to the outer objects is, in reality, to their subtle imprints in the mind. Like every thought, feeling and emotion, every object-imprint in the mind also rises and sets in the mind itself. How can we then adduce unbroken existence for any external object or its experience?
Thus, it has to be clearly borne in mind that in our experience of the world, our own inner mind and its imprints act as the sole basis. Therefore, we have no ground to say that the objects exist in their own right, with grossness and distinctions, as they seem to suggest. All are, in truth, the mind alone and the imprints it causes. This is the fact, judged by our own intelligence and reason.
This statement, in fact a summary conclusion on the basis of rational study, should always remain in the mind of the seeker. At no time, should he allow it to dim or dwindle. In that lies the success and the wholesomeness of his seeking.
Click here to read the article by Swami Bhoomananda Tirtha 'Illusoriness of Seen Objects': https://www.bhoomananda.org/writings/illusoriness-of-seen-objects/