It's all a simulation!
Advaita vedānta gets as close as anyone ever has to answering the question about the true nature of reality, and it posits that the world is an illusion and the only 'truth' is the supreme consciousness. There is an amazing Sanskrit shloka (composed in the 8th century CE) that I came across that articulates this in the simplest way possible.
स्वप्नेऽर्थशून्ये सृजति स्वशक्त्या
भोक्त्रादिविश्वं मन एव सर्वम् ।
तथैव जाग्रत्यपि नो विशेषः
तत्सर्वमेतन्मनसो विजृम्भणम् ॥
भोक्त्रादिविश्वं मन एव सर्वम् ।
तथैव जाग्रत्यपि नो विशेषः
तत्सर्वमेतन्मनसो विजृम्भणम् ॥
svapne'rthaśūnye sṛjati svaśaktyā
bhoktrādiviśvaṃ mana eva sarvam |
tathaiva jāgratyapi no viśeṣaḥ
tatsarvametanmanaso vijṛmbhaṇam ||
bhoktrādiviśvaṃ mana eva sarvam |
tathaiva jāgratyapi no viśeṣaḥ
tatsarvametanmanaso vijṛmbhaṇam ||
There are no real objects in dreams, and the mind alone, by its own power, projects the entire universe (including the experiencer).
Likewise, upon waking there is no fundamental difference. All of this too is merely the mind’s own play or projection.
Likewise, upon waking there is no fundamental difference. All of this too is merely the mind’s own play or projection.