"Immigrants have added so much since. They have helped our economic life, not just in providing labour and consuming goods and services but also by adding dynamism and entrepreneurial vigour. In cultural terms, immigration has helped to make Australia a more vibrant and interesting place where ideas from around the world combine to inspire creativity. Propelled by this energy, both Sydney and Melbourne have grown into globally-recognised cities of cultural significance."

Had the author been referring to settlement since 1788, he might be condemned as a racist. The statement would seem to imply that indigenous populations become dull and unproductive without a constant influx of migrants, much like the Japanese have over the centuries I would suppose.

If Mr Varghese were dropped in the Australian outback, I'm sure that his dynamism and entrepreneurial vigour would prompt him to enthuse about turning the desert into an oasis replete with fungating metropoli. But somehow I think that the dull and unproductive indigines would be surviving long after his departure.

When immigrants are (generally) intelligent (middle class, educated) people who are fleeing prolems in their own countries, then immigration benefits Australia. Otherwise it doesn't!

For example, During Hitler's time, the European Jews fleeing Europe were generally highly intelligent people. In general, people who have the energy, money and education (intelligence) to get out of a bad situation, are generally the most resourcefull and intelligent people.

But lets not generalise that ALL immigrants are like this.

FOr example around 70% of Afgan-born Australian citizens are welfare-dependant. Now our unemployment rate was well-under 10% and few Afgan immigrants came to Australia before the 1980's, so they weren't on old-age pensions... basically, they are dole-bludgers.

How do I know this? In 2001 the Department of Immigration had on it's web site the rates of welfare dependance of various immigrant groups. It's not available now :-)

So
When immigrants are clever, it benefits Australia. But when immigrants are generally "economic" migrants, there is not a benefit for Australia, only a COST.

Howard's changes to immigration meant for people to get here, they had to earn 'points'; education, desirable skills, wealth, English language... without being an IQ test (too politically incorrect), it was pretty close to that! And consequently Howard managed to INCREASE immigration, despite the huge public anger about 'immigration' under the Keating/ALP government... and the formation of the "One NAtion" Party.

Which basically says smart people help Australia, dumb ones don't.

Why has immigration become a pseudo-religion? You either believe it is good, or you rot-in-hell? What's wrong with the truth, that there are good and bad migrants? and IQ is the determinimg factor

Most respondents attacking the article (and, disappointingly, also the author) start from the assumption that Australia and the rest of humanity are on the verge of cooking the planet, running out of water, and other apocolyptic events.

Such apocolysim is an invariable feature of public debate through the ages. It is also invariably wrong.

Its peddlers take a current trends, extrapolate it forward, and then claim we are all doomed. But humans and the natural world are not like an Excel spreadsheet.

Take the idea we are running out of food. Food shortages raise the price of food, encouraging more investment in existing technologies as well as the development of new ones. For instance, genetically-modified plants can increase crop yields while also reducing the use of pesticides and herbicides.

Population alarmists ignore the human capacity for problem-solving and adaption. I would like to think the reason is ignorance. But I fear it is prejudice - the idea that "we" already living in Australia are doing fine, and "others" can rot in their own poverty.

This raises the biggest shortcoming of critics' responses to the article. They fail to address the key challenge set out by the author: "For as long as we have space, peace and resources some people from crowded, violent or poorer countries will want to make a home here. Who are we to stop them?"

By all means, admit you believe people already living in Australia deserve a better life than people who don't. Whatever you choice of bigotry - race, nationality, religion, intelligence (partTimeParent - Do you know why my migrant parents were "dumb"? Because they had to leave school at age 10 to work. Their children, able to finish school and go on to university, won many academic awards and now fill professional positions) - don't pretend that, morally speaking, you are fit to even tie the author's shoelace.

Banjo: "The major political parties receive big donations from developers and big business, so do their bidding."

I think a slight variation on that is true, Banjo. The major political parties are driven foremostly to get re-elected, and then by ideological concerns. Big donations are but one factor in getting them re-elected.

Another way of saying the same thing is they can capable of doing just about anything - good or bad, provided they think they can still get elected next time around.

My guess is they have been convinced if they stop immigration the economy will tank shorting thereafter, resulting in them being removed from office at the next election. The cynic in me says they know continually growing the population will eventually tank the entire country, but since that will happen outside of this electoral cycle they don't care. The realist in me says they have enough people around them telling them this won't happened that they have convinced themselves it must be true.

Sibba: "Who are we to stop them?"

We are selfish bastards who have the view that in the time scales we are talking about, every society has the opportunity to do what Iran has recently done and take control of their population growth. Or not, as the case maybe. It is their choice, and they have to live with the consequences of their decisions - as do we.

We probably would not be quite so selfish if they would listen to our advice on population size. But they don't, I guess for the understandable reason that people don't like being told by others what they can do in their own bedrooms. Nor would we be quite so selfish if it wasn't patently obvious that we have hit the limits in the country in the amount food we can produce, and the oil and water available.

Finally, expecting us to not believe what we see with our own eyes, and instead bet our future and that of our children and grandchildren on your assertion that earth is a magic pudding is asking far too much.

Sibba seems to be awfully bigoted about people who support sane and sustainable population policies. In typical form for bigots, Sibba assumes that there can only be one reason for supporting a halt to immigration, and completely ignores the resource and environmental issues. Nowhere is it written that any sovereign country has to drop its borders to welcome one and all from any part of the world. Is it selfish to wish to preserve what little is left of the natural world so that our children and grandchildren can enjoy it too?

rstuart - Your assertion - "Nor would we be quite so selfish if it wasn't patently obvious that we have hit the limits in the country in the amount food we can produce, and the oil and water available." - is just that.

The amount of food we can produce is a function of the inputs required (land, sun, water, energy, and so on) and the productivity with which we use them.

The supply of some inputs is limited, at least at any point in time. These include water and land.

The supply of others, notably the sun, is unlimited.

And the productivity of farming is also uncapped, especially when you consider the advance being made in biotechnology.

Add all this together and it is "patently obvious" you have no excuse to be selfish.

In any case, do you really think that, if the future is as dire as you claim it will be, underfed, sweltering, cramped people in other countries will just leave Australians to their underpopulated paradise?

Ultimately, we are only as secure as our neighbours are. A world made up of isolated, inward-looking nations is an unstable and dangerous one.

This is not wild-eyed idealism but realpolitic.

Further, your knowledge of Iran is hazy at best. The recent drop in the birthrate has nothing to do with taking "control of their population growth", and everything to do with the education of young women in that country.

You continue: "Finally, expecting us to not believe what we see with our own eyes, and instead bet our future and that of our children and grandchildren on your assertion that earth is a magic pudding is asking far too much."

You need to look again. The fantasies you see are through eyes laden with prejudice and lack of empathy. Close your eyes, imagine yourself in a poor country with little food and no water, seeking a better life for your children. Then open them again, and look afresh at the peace and plenty around you. If are you still unmoved, then I pity you.