Another uncontacted tribe has been discovered in Brazil's rainforest. Norman Geras poses a thought experiment:

Suppose there is a site of extraterrestrial life somewhere very far off and that the life in question is not only intelligent but also – miraculously – human. These are human beings, what is more, who are technologically much further 'ahead' than we are. They have the means to detect us and they have detected us, and they have the means to travel across the vast spaces they need to in order to come and shake our hands. Do they owe it to us to forbear – to leave us alone?  …

[Imagine] that those extraterrestrial humans had already found ways of solving social, medical or other problems still bedevilling us here on Earth. Suppose, similarly, we could help extend the lifespan of the average rainforest tribesperson by 50 per cent.

Previous Dish coverage of isolated tribes here, here and here. Above is a long but captivating video of the Toulambi tribe of Papua New Guinea meeting a white man for the first time in 1976.