Kallis makes some valid points. But he was not able to show the practical implications of these points, or dawdled quite a bit in making them. So even though this book is fairly short (139 pages), I couldn't quite get into it and wound up reading only about half of it. I skipped forward and back to see what his point was, and couldn't find it.
But first, what he got right. What? Malthus is wrong? We all thought that Malthus was the first person to talk about limits to economic growth. It sounds the author is going to make a pro-growth argument, but cheer up! Malthus, strictly speaking, doesn't advocate a "limits to growth" point of view, in the sense of some absolute limit on the economy. Malthus is actually pro-growth. He only says there is a limit on the rate of growth. The economy can grow indefinitely, just not at an exponential rate. It's the difference between an "arithmetic" progression (1, 2, 3, 4, 5) and a "geometric" progression (1, 2, 4, 8, 16). In fact, as a percentage of existing size of the economy, the rate of growth will continuously decline. There will be some exceptions for improvements in technology and discovery of new resources; but technology can never be more than 100% efficient, and new resources are still finite.
But that's not the way that most people, including me, read Malthus. Most people read Malthus as saying "because there are limits, you can't always get what you want," and that there is an unstated corollary here: not only can economic growth not progress exponentially, at some point it can't progress at all. That's how Darwin read Malthus, who was a central influence on the theory of evolution. Even though Malthus didn't say "there are absolute upper limits on the economy," we generally consider Malthus to imply this. Consider Malthus duly chastised for not clarifying this. Can we move on?
I think that what Kallis wants to add to the discussion is that the real problem is our unlimited wants, not nature. True enough; with unlimited wants, we're bound to have a problem no matter how "big" nature is. On p. 45, he distinguishes between environmentalists in the 1970's who wanted to limit growth because it destroyed the environment, and those who wanted to limit growth because otherwise the economy would crash and burn. On page 50, he says, "it is not our nature but the system that wants us to want without limits."
These are all valid points, but to me it is a distinction without much practical impact. So are we against the growth economy because it distorts our human nature or because it destroys the earth? Well, either way, we're against it. If I was talking to a Buddhist audience, I'd emphasize the first problem. You'll never get to enlightenment if you buy into the growth economy! But if I was talking to a bunch of Republicans, I'd emphasize the second. Profits will be down if you destroy the planet!
There are other issues for which the same sort of distinction could apply. For example, the arguments for veganism. Some believe it's wrong to eat animals, but others believe it's bad for your health and for the environment. There are practical considerations versus moral considerations. But either way, we still should go vegan. Most vegans come to veganism through one of several paths --- nutrition, ecology, or ethics. But once they get there, they see the validity of the other paths. They broadly agree on both the health angle and the ethical angle to veganism. There are some exceptions, but if you talk to vegans this is what you'll typically hear.
Another issue in which this distinction is applied is the philosophical arguments about utilitarianism versus deontology. A utilitarian would say that murder is wrong because it's a bad idea and people get hurt. A deontologist would say that murder is just wrong, period. But either way we get to the same result.
Yes, it MIGHT make a difference, and you can come up with some convoluted cases where it would. But in practice it's hard to see what it is. Most philosophers (and others) agree that you should lie to a murderer who comes to your door and wants to kill the person hiding in your basement. Most environmentalists would be against damming the Grand Canyon to produce electricity.
So, bottom line: I see his point and I think I agree with it, but it's hard to get into. First of all, he seems to misinterpret Malthus through an over-literal reading. But second, he wants to take this distinction and draw practical implications. Show me these practical implications, I just don't see them. I'm a little busy right now trying to save the ecosystem. Can we just stop economic growth already?