Which kind of reality do humans actually perceive? Is it a reality as it is, or is it a reality, which has been directed by our brain functionality that is shown to us?
Often it is assumed that the brain is permanently active. But is that really so? Experiments in the past have shown that the human brain rather works in cycled time intervals. This has a huge influence on the way the world is perceived. For example, if the same tune is sent out twice within a very short time interval the human brain will perceive it as only one tune. The same way the human brain acts as some kind of film director when seeing things. Multiple and successive sight impressions caught in a certain timeframe will be captured as a single composed image by the human brain.
Those examples show us that because of this functionality a human being can perceive the phenomena around him only in a distorted and selective way. It also shows us that the brain is not permanently active but rather reacts in intervals on the stimulations it perceives through the senses.
It is this functionality of perceiving and processing that is considered to be switched off completely during anesthesia. Even during sleep the brain keeps on processing sensations. But more in the background like dreams taking place. That is why a person is still able to estimate what time it is when he wakes up from sleep. If a person wakes up from anesthesia though, he is really disorientated because that particular brain functionality has been disabled for some time.
Also where space is concerned, humans do not really experience space. They rather develop a sense of space according to the phenomena they perceive. Space perception is more a way through which humans become aware of their own position in relation to the objects around them. Space does not really exist as an individual object.
Although space is mainly derived from vision, also the other senses or a combination of them play an important role in the process of perceiving space. When, for example, a person hears the humming sound of a bee, he knows by experience how loud the humming of a bee normally is. Subsequently, according to the volume that he hears, his mind makes an estimation of how close the bee is in relationship to his own position.
So what is time and space then really? Are these things that are really out there in the world, or are these just concepts produced by consciousness? Thinking in terms of time and space is not really something a person needs to learn in school or from some books. Phenomena are rather instinctively positioned in time and space.
Nevertheless perception of space, like all sorts of perception, only brings some kind of selective and therefore illusionary reality. Since the human mind is not capable to capture nature in its entity, it is the selective process of perception that saves the individual from complete disorientation. In this process it is the human brain that models the overflow of sensations in some kind of variants or images of reality, which can be handled by the individual.