大乘起信論裂網疏 4.100

4.100

This first contemplates that the aggregate of physical form is unestablished. If a subtle atom has directional parts, then it can be analyzed and is definitively not real; if it has no directional parts, then it is not physical form. Therefore, one knows that all gross and subtle physical forms are mere objective aspects manifested by the deluded mind; outside of the mind there is truly no physical form.