We can if we read all contributions see some have zero interest or is it ideas? on what our population should be, or if it will ever be too large apathy is never an answer, it however is always a problem, could say more about that but just can not be bothered

I agree that it's pointless arguing with those that are never going to agree with you. Generally its just as easy to talk past them but sometimes it's good to have a little fun. See how much rope you can roll out. ;) But for those that believe that population is a problem - what would you think is the best way to deal with the problem, and how would you implement it?

//Toni Lavis said "Yeah, but Malthus was wrong. Quoting him as an authority is a crap argument."

Answer - Is quoting yourself as an authority any less.//

http://www.youtube.com/watch?v=6-JfIduytVs

Is quoting yourself even a thing? It's times like this I wish I'd paid more attention in my English classes.

Anyway, I hardly consider myself an 'authority' on Malthus. To be honest, I've not read his work. I learnt about him when I studied philosophy, and his work was used as an example of 'why sound reasoning can lead to erroneous conclusions when the fundamental premises are wrong'.

And his reasoning was sound, but his premises weren't. He assumed that the population growth was exponential (correct-ish) but that the growth of the food supply was linear. That second assumption was dodgy: the growth in food supply wasn't linear, human ingenuity found ways to boost crop yields to keep up with the burgeoning population. So his conclusions were also dodgy. A textbook example of an argument that is logically valid, but unsound due to a false premise.

individual,
The Polynesian seafarers' knowledge was based more on successes than failures. For those who died at sea can't tell you anything, but those who come back alive can.

They did not just find land by chance. They learned, before they ventured out into the unknown, things like how the presence of land affects the wave patterns for much further than the land is visible from.

_________________________________________________________________________________

Canem Malum,
The world's fertility rate has already dropped below replacement levels, but the population is still growing because people are living longer.

And air pollution has little to do with population - it's much more to do with lack of, or lack of enforcement of, environmental regulations.

Thank you Tovi Lavis for your comments...

Please let me know if you see any glaring mistakes.

From what I understand (not having studied Economics formally) Malthus in the 1790's based his "productivity is arithmetic in time" argument (which he removed in his second edition) on the Law Of Diminishing Returns. Perhaps he took some liberties. However he was basically saying that the order of magnitude of population increase upper limit was e^T (Toni Lavis made some concession on this point) but the magnitude of production was lower due to the Law of Diminishing Returns. So as a population grows there is a greater mismatch between the size of the population and the nations productivity leading to a sudden population correction.

Based on the multifactor production function Q = D.L^a.K^b.R^c ie. Q~ L^a.K^b.R^c where
Q= production
L= Labour
K= capital
R= resources (includes land area)
D= constant
a,b,c are diminishing return factors dependent on the production system existing in range [0,1] such that a+b+c <= 1 (=1 in a perfect system)
=> if R (is land) is constant then productivity will suffer by a factor R^c so if c= 1/3 then if population changes as e^T then productivity scales has an upper limit around e^(T/3). This means the mismatch between population and productivity varies about e^(2T/3) in this model.

This e^(T/3) ~/~ T so Malthus strictly speaking is incorrect in saying that productivity scales with T - but his essential point still appears to stand "in this model" - that there is a growing mismatch between population growth and productivity growth. Changes in technology would appear to change D - perhaps by an order of magnitude - given that technology changes are unpredictable and product specific it may not be possible to avoid the "sudden population correction". But technology appears to also have an e^T relationship - maybe this could be researched further.

There is also the issue of individuals living in constantly decreasing personal space could develop psychological illness.

Overall it appears that caution is warranted and population should be controlled to avoid sudden population corrections.

Dog,

Towards the end of your last post, are you suggesting that people in densely-populated countries such as the Netherlands or Bangla Desh experience many more psychological problems that people in, say, Mauritania or Kazakhstan ? Horrors !

Given that your Q, L, K and R are all manipulable, changeable, your constant D doesn't look all that constant :) You omit the impacts of social policies and the social consequences of advances in all of your input factors, such as the assertion around the world of women's rights and the concomitant demand, and experience, of higher levels of education for women. These in turn help more women get into the work-force at higher levels, and out of all that comes a much lower fertility rate. This is probably happening in every country (please correct me if I'm wrong there).

I would respectfully suggest that the growth rate of world population is declining more rapidly than even the UN acknowledges. Yes, many countries in the Third World will not have the finances to implement an age-pension scheme for a long time yet, so birth-rates in those countries will remain high - but, on the other hand, not as high as hitherto since health services are slowly improving across the globe. The 'demographic transition' will still take some time to come about in those countries, since it usually takes a generation for people's decisions to catch up with social and health improvements.

One thing I'll say about China's disastrous one-child policy, though: officially at least, national minorities were exempted from the one-child rule. So their fertility potential is much greater (and social burden lighter) than for China as a whole. Their share of the national population should have risen noticeably and should continue to do so.

Cheers,

Joe