Earlier this year the American professor Bruce Gilley was attacked for publishing an article arguing that the British Empire had some benefits. Let's look at one particular case of the British Empire in action, the case of New Zealand.
If you live in New Zealand, you'll hear a lot about the sins of Empire. About how British settlers made things worse for Maori in virtually every way.
But imagine you were an alien scientist, sent from another planet specifically to track how the Maori were doing. Let's say you visit in the early 19th century, before the British started to come in large numbers, and then visited again today. One of the things you'd want to look at would be how many Maori there were. And you'd find that there were a few more:
A lot more, in fact. You'd find that the Maori population had increased from less than 100 000 in the mid-19th century to almost 800 000 today.
Not only that, but you'd find that the pre-modern society you'd encountered in the early 19th century had been transformed. You'd find that Maori were living longer (with life expectancies more than twice what they were). You'd find that Maori were much more prosperous (with per capita GDP skyrocketing from the level of a pre-industrial economy to that of a first-word country).
You'd find that Maori were living in warmer houses, that the burden of disease had plummeted, and that they were better educated, with a more accurate picture of the world beyond their immediate environment. You'd also find that Maori culture was flourishing like never before, with high-quality carving showcased in marae all over New Zealand, and with the haka admired in faraway cities like London and Paris.
You'd even find that there were a few more people able to speak the Maori language - far fewer as a percentage of the Maori population (about 20% on your second visit), but a few more overall than the total Maori population on your first visit (20% of 800 000 is still 160 000).
Of course, as a good alien scientist, you wouldn't want to jump to any conclusions about what caused this transformation. But a working hypothesis would be staring you in the face: that this transformation had something to do with the pale-skinned outsiders who'd arrived from a distant part of planet Earth.
You wouldn't necessarily need to conclude that the outsiders increased Maori living standards on purpose. You might prefer to hypothesize, for example, that they simply acted as a conduit for more advanced technologies and ways of doing things, which in turn powered the positive changes.
But in any case, the facts you found on the ground on your second trip to New Zealand (and to Earth) would rule out one course of action. If you went back to your alien overlords and told them, 'Some new settlers arrived and made everything worse for the Maori,' and then relayed to them the improvements mentioned above, they'd think you'd been inhaling too much of the Earth's atmosphere.
Now, if you were a very sensitive and careful alien scientist, you might well want to add some details to your report. About how you found evidence that some of the outsiders had pressed some pretty dodgy deals in terms of land purchases, and that the they sometimes used force to found their new state, which was for a long time dominated by the outsiders themselves. But you'd also want to add that by the time of your second visit, there was nothing barring Maori from political activity, and that the outsiders were making great efforts to make amends for the transgressions of some of their ancestors.
If your alien overlords looked very carefully at your data, they might notice that Maori still lagged behind the outsiders in various measures of the quality of life, despite the vast improvements in their own population. But they'd doubtless put that down to the different starting positions of the two groups, one of which was already an industrial society when they arrived, while the other was still living in pre-modern conditions. They'd doubtless think about how quickly Maori living standards would have improved had the outsiders not come, and conclude that progress would have been slow and uncertain.
That's probably enough of that thought-experiment. The point of it was, I hope, obvious enough: to step back from the current orthodoxy within New Zealand universities and look at the facts in the way that a dispassionate observer might. (The progress of post-colonial theory in universities has meant that it's more difficult than you might think to find a dispassionate observer on this planet.)
If we do that, the facts speak clearly: Maori are better off in virtually every way than they were before the British settled New Zealand. That doesn't mean that no British settler ever did anything wrong. It doesn't mean that absolutely nothing was lost in the great transformation of Maori life over the past few hundred years. And it definitely doesn't mean that we should go back to the early days of New Zealand history, when Maori were effectively excluded from many areas of life.
But it does mean that the net effect was positive - indeed, spectacularly positive. More cautiously we can say that it suggests that Gilley is right, and that the British Empire did have some positive effects (whether it did so consciously or on purpose is another question). But don't expect our alien sicentist's data to be highlighted in a course in any New Zealand university nowadays.