How do we know we're not...
...neurones in the Mind of God, albeit a 'god' who is a macro-level entity composed of us, just like our cells compose us? Super-organisms and all that kind of thing. To me a community of people who carry a common meme (or have sufficient memes in common) are homologous to individual bodies and our DNA.
Of course the meme-set that acts as the 'DNA' of super-organisms may need periodic renewal and may be full of parasitic elements, akin to retroviruses and transposons. Whether the concept of an actual "Creator God" is one of those is up to the individual - personally I think that regardless of God's ontological status, the conception in most people's heads needs serious work.