I totally agree with /u/TheLuteceSibling and /u/pocketjpaul that this may be an unanswerable question.

BUT...*if* conciousness is an emergent property of complex systems (which is one of the competing theories but we may not be able to confirm), then you go into the general space of emergent properties, which is that you get properties of systems that are *more* than the sum of their parts because the "thing" is the interactions, not the parts.

A bunch of lightly-electrified cells *aren't* conscious. Dopamine isn't happy. But the interaction of a whole bunch of dopamine (and other stuff) mediated lightly-electrified cells results in a network/interactions that are conscious. It's the relationship between the things, not the things themselves, that defines the phenomenon.

It's roughly like pointing at a wave and saying "how do a bunch of water molecules make a wave?". The water molecules have no idea that they're part of a wave and "the wave", which is a perfectly visible measurable predictable thing, is made up of different water molecules from moment to moment but it's still "one wave". It's the interaction/relationship between water molecules that defines the wave, not the molecules themselves.