The world is the objective reality, the collection of independently existing things – space, objects and time. Space is a special kind of object. Time is the interaction of space and objects.
Loss of the ability to maintain awareness of self and environment combined with markedly reduced responsiveness to environmental stimuli. (From Adams et al., Principles of Neurology, 6th ed, pp344-5).
The question, then, is whether activity (perception) occurs in the mind (brain) during unconsciousness. Can or does perception continue? Do we interact with the mind-objects, the concepts we have acknowledged (gained knowledge of) even after the sensation of space-objects is shut off?
It should be noted, firstly, that the concept of Emptiness (shunyata) does not exist in the Theravada tradition of Buddhism. It is a Mahayana Buddhist term. The term closest to Emptiness in Theravada Buddhism is Non-self (anatman). So why these separate terms?
In Theravada Buddhism the Buddha’s teaching of Non-self is interpreted to mean only no essence of the self, the sentient being. Mahayana Buddhism interprets Non-self to mean all things, animate as well as inanimate. This is why Mahayana Buddhists to distance themselves from the term No-self by taking a word to cover the wider definition they believed the teaching of Non-self to mean.
This is why Form and Emptiness are spoken within the same breath in the Heart Sutra. Whether one accepts the Theravada or Mahayana is up to the individual. What is important is to know at least this difference exists in Buddhism. It is a matter of interpretation.
If ever there were important discoveries they are these.
The Buddha said there are three marks of existence – impermanance, suffering and no-self. Everything (yes, everything) in the world is impermanent. There are no exceptions to this. We suffer because we think there is something permanent. It doesn’t matter what that thing is, if one thinks it is permanent then we suffer the consequences for that belief. More often than not the thing we believe most to be permanent is the self. And The Buddha unequivocally states even this is impermanent.
Know that there is no self would end suffering which in turn leads to the understanding of impermanence.
But coming to this understanding is harder than it sounds. It usually takes years of training. When you have achieved this, though, rest assured you will be enlightened. Good to know, isn’t it.