They’re not the same.
Many people are under the impression that the ultimate truth of Buddha Dharma is a ‘non-affirming negation’, that is, an understanding of reality as void, null, non-existent.
While the Buddha encouraged us not to be fooled by appearances and to stop ascribing independent existence to that which is temporary and dependent, it is a misunderstanding to interpret his teaching as promoting ‘nothing’ as the ultimate truth.
This misunderstanding is often based on the sutras of the Second Turning of the Wheel of Dharma:
Form is empty, emptiness is form. Emptiness is not other than form, form is also not other than emptiness. Likewise, sensation, perception, volition, and consciousness are empty.
In this way, all things are emptiness; they are without defining characteristics; they are not born, they do not cease, they are not defiled, they are not undefiled. They have no increase, they have no decrease. —Heart Sutra
All things are empty. No thing is truly established –no thing exists independently of the consciousness that perceives it. But does this mean that reality is nothing?
Kunchen Dolpopa Sherab Gyaltsen says, in The Fourth Council:
The meaning of the Second Dharma Wheel is Thusness, with complete infinite qualities. It is not a non-affirming negation; it is not an emptiness of self-nature, an emptiness of nothingness, or a nihilistic emptiness.
When the unreal is set aside, when we no longer place our trust in things, what remains is non-dual pristine awareness.