That leaves hanging a really strange chicken-and-egg question about creation and evolution, but it's worth reading Bloch's essay, published here in Philosophical Transactions of the Royal Society B and discussed in this article on NewScientist.com. As you may have surmised from Bloch's background, his article is based more conjecture than lab work:
Uniquely, humans could use what Bloch calls the "transcendental social" to unify with groups, such as nations and clans, or even with imaginary groups such as the dead. The transcendental social also allows humans to follow the idealised codes of conduct associated with religion.
"What the transcendental social requires is the ability to live very largely in the imagination," Bloch writes.
"One can be a member of a transcendental group, or a nation, even though one never comes in contact with the other members of it," says Bloch. Moreover, the composition of such groups, "whether they are clans or nations, may equally include the living and the dead."
Modern-day religions still embrace this idea of communities bound with the living and the dead, such as the Christian notion of followers being "one body with Christ", or the Islamic "Ummah" uniting Muslims.
No animals, not even our nearest relatives the chimpanzees, can do this, argues Bloch. Instead, he says, they're restricted to the mundane and Machiavellian social interactions of everyday life, of sparring every day with contemporaries for status and resources.
And the reason is that they can't imagine beyond this immediate social circle, or backwards and forwards in time, in the same way that humans can.
Bloch believes our ancestors developed the necessary neural architecture to imagine before or around 40-50,000 years ago, at a time called the Upper Palaeological Revolution, the final sub-division of the Stone Age.
At around the same time, tools that had been monotonously primitive since the earliest examples appeared 100,000 years earlier suddenly exploded in sophistication, art began appearing on cave walls, and burials began to include artefacts, suggesting belief in an afterlife, and by implication the "transcendental social".
Once humans had crossed this divide, there was no going back.