In [how smart can I make ants](https://worldbuilding.stackexchange.com/questions/45037/how-smart-can-i-make-ants), an idea was suggested, to instead of making each ant individually sapient, [make the 'anthill' as a whole sapient](https://worldbuilding.stackexchange.com/a/45046/885); a kind of unconventional hive mind. Just as a familiar anthill is more like a single body whose organs happen to not be stuck together, my alien intelligence develops on the level of a colony. Just as a single brain cell is not a mind, a single bug is not sapient. To quote the accepted answer:

> 
> It is the level of a colony that has a single DNA and evolves as an
>  animal. Individual workers are no different than our individual cells
>  which are replaced from within as they wear out. The colony has intent
>  and direction and will decide when to move or camp, flee or fight,
>  discover new food resources and hold social relations with other
>  colonies. The individual bugs communicate via hormones etc. just as
>  the cells and organs within a body coordinate, but are one system.
> 
> 
> 

In summary, the basic concept here is that hundreds of thousands (if not millions), of small creature are able to make up one big creature, in the same way cells make up humans. Ever since hearing this answer, I have become obsessed with this idea but I, as a hard-science fiction worldbuilder, must know if this concept is at all realistic. So, is this concept of a collective consciousness realistic? And if so, how would it develop from regular ants?