Formlessness can birth Form (can give rise to Firm) but Form cannot birth Formlessness (cannot give rise to Formlessness). Formlessness is freedom.
Form is a limitation of freedom. Freedom is free to indefinitely restrict itself into a Form.
Restriction (Formlessness-restricted-into-Form) cannot free itself. Restriction can only continue to restrict itself indefinitely.
Consciousness (awareness) is formlessness.
Mind (intellect) is form.
Consciousness (the Field) can be aware of this or that mind-form that it birth (like a given Gestalt background brackets a figure).
But a mind-form (a moment-specific instant of intellect) cannot (is not free to) grasp/understand the formless consciousness that birthed it in the first place.