When I was a youngster in school, the "Great Famine," also known as "The Irish Potato Famine," was taught in depth in history classes. It is a very important event in human (and American) history and is very informative, even necessary, to understand in order to be proficient in economics and what I have been explaining about capitalism having to mindfully treat subsistance and surplus product using totally different risk profiles. So before I explain more about why the Great Famine is so instructive about understanding true capitalism, read here some excerpts from the Wikipedia entry.
The Great Famine (Irish: An Gorta Mór or Irish: An Drochshaol), also known as the Irish Potato Famine and the Great Hunger was a famine in Ireland which started in 1845, lasted — depending on the region — until 1849 or even 1852 and which led to the death of approximately one million people through starvation and disease; a further million are thought to have emigrated as a result of the famine. Some scholars estimate that the population of Ireland was reduced by 20 to 25 percent.
The proximate cause of the famine was a potato disease commonly known as late blight. Although blight ravaged potato crops throughout Europe during the 1840s, the impact and human cost in Ireland — where a third of the population was entirely dependent on the potato for food — was exacerbated by a host of political, social and economic factors which remain the subject of historical debate.
The famine was a watershed in the history of Ireland. Its effects permanently changed the island's demographic, political and cultural landscape. For both the native Irish and those in the resulting diaspora, the famine entered folk memory and became a rallying point for various nationalist movements. Modern historians regard it as a dividing line in the Irish historical narrative, referring to the preceding period of Irish history as "pre-Famine." The fall-out of the famine continued for decades afterwards and Ireland's population still has not recovered to pre-famine levels.
Although central to everyday life, the Irish potato crop was an uncertain quantity. The famine of 1845 was notable for its vastness only: according to the 1851 Census of Ireland Commissioners there were twenty-four failures of the potato crop going back 1728, of varying severity. In 1739 the crop was "entirely destroyed", and again in 1740, in 1770 the crop largely failed again. In 1800 there was another "general" failure, and in 1807 half the crop was lost. In 1821 and 1822 the potato crop failed completely in Munster and Connaught, and 1830 and 1831 were years of failure in Mayo, Donegal and Galway. In 1832, 1833, 1834 and 1836 a large number of districts suffered serious loss, and in 1835 the potato failed in Ulster. 1836 and 1837 brought "extensive" failures throughout Ireland and again in 1839 failure was universal throughout the country; both 1841 and 1844 potato crop failure was widespread.
The 1841 census showed a population of just over eight million. Two-thirds of those depended on agriculture for their survival, but they rarely received a working wage. They had to work for their landlords in return for the patch of land they needed in order to grow enough food for their own families. This was the system which forced Ireland and its peasantry into monoculture, as only the potato could be grown in sufficient quantity. The rights to a plot of land in Ireland could mean the difference between life and death in the early 19th century.
Ireland remained a net exporter of food even during the blight. The immediate effect on Ireland was devastating, and its long-term effects proved immense, changing Irish culture and tradition for generations. The population of Ireland continued to fall for 70 years, stabilizing at half the level prior to the famine. This long-term decline ended in the west of the country only in 2006, over 160 years after the famine struck.
Following earlier reports of its incidence in England, on 13 September 1845 potato blight was first reported in Ireland. By mid October it was widespread. The Prime Minister Robert Peel was prompted to act. On 15 October he decided that this was the time to repeal the Corn Laws to reduce price of grain/bread for the poor. On 18 October Peel set up a Scientific Commission to go to Ireland and investigate the potato blight and report on conditions. An emergency Cabinet meeting on 31 October - 1 November instituted a Relief Commission plus other measures to alleviate distress but Peel's proposal to repeal the Corn Laws was rejected On 9-10 November Peel ordered the purchase of £100,000 worth of Indian corn from America for distribution in Ireland. On 15 November the Scientific Commissioners reported that half the potato crop had been destroyed. On 20 November the Relief Commission first met.Unable to convince his Cabinet to repeal the Corn Laws, on 5 December Peel tendered his resignation to Queen Victoria but was reinstated days later when Lord John Russell was unable to form a government.
The first deaths from hunger took place in early 1846.In March Peel set up a programme of public works in Ireland but was forced to resign as Prime Minister on 29 June.The new Whig administration under Lord Russell, influenced by their laissez-faire belief that the market would provide the food neededthen halted government food and relief works leaving many hundreds of thousands of people without any work, money or food.Grain continued to be exported from the country.Private initiatives such as The Central Relief Committee of the Society of Friends (Quakers) attempted to fill the gap caused by the end of government relief and eventually the government reinstated the relief works, although bureaucracy made food supplies slow to be released.The blight almost totally destroyed the 1846 crop and the Famine worsened considerably.By December a third of a million destitute people were employed in public works.
1847 ("Black '47")
1847's exceptionally hard winter made conditions even worse.A typhus epidemic killed tens of thousands, including wealthier people as the towns were now also affected. 1847's harvest was largely unaffected by blight but too few potatoes had been planted so the Famine continued unabated. The Soup Kitchens Act provided financial assistance to local authorities to help them feed Famine victims but this Act was withdrawn in September and relief was made the responsibility of local poor rates and of charitable organizations.This put impossible loads on local poor rates, particularly in the rural west and south. Emigration reached new heights and the infamous coffin-ships crossed the Atlantic in large numbers carrying people fleeing from the famine.
The blight returned in 1848 and outbreaks of cholera were reported.Evictions became common among the Irish who couldn't keep up with the demands of their British landlords. Famine victims on outdoor relief peaked in July at almost 840,000 people. On 29 July an uprising against the government was led by William Smith O'Brien. After a skirmish at "Widow McCormack's house" in the village of Ballingarry, County Tipperary the leaders of the rebellion fled to America or were sentenced to transportation.
The potato crop failed again in 1849 and famine was accompanied by cholera outbreaks.This deadly cholera epidemic kills one of Ireland's greatest poets: James Clarence Mangan.
The Famine ends.
By 1851 census figures showed that the population of Ireland had fallen to 6,575,000 - a drop of 1,600,000 in ten years. On the 1851 census both Cormac Ó Gráda & Joel Mokry would also describe it as a famous but flawed source. They would contend that the combination of institutional and individuals figures gives “an incomplete and biased count” of fatalities during the famine. The famine left in its wake perhaps up to a million dead and another million emigrated.The famine caused a sense of lasting bitterness by the Irish towards the British government, whom many blamed — then and now — for the starvation of so many people. The fall-out of the famine continued for decades afterwards.
Claims of potato dependency
Jeremy Rifkin, in his book Beyond Beef, writes "The Celtic grazing lands of...Ireland had been used to pasture cows for centuries. The British colonized...the Irish, transforming much of their countryside into an extended grazing land to raise cattle for a hungry consumer market at home.... The British taste for beef had a devastating impact on the impoverished and disenfranchised people of...Ireland.... Pushed off the best pasture land and forced to farm smaller plots of marginal land, the Irish turned to the potato, a crop that could be grown abundantly in less favorable soil. Eventually, cows took over much of Ireland, leaving the native population virtually dependent on the potato for survival (pp. 56,57)."
One possible estimate has been reached by comparing the expected population with the eventual numbers in the 1850s (see Irish Population Analysis). Earlier predictions expected that by 1851 Ireland would have a population of eight to nine million. A census taken in 1841 revealed a population of slightly over 8 million. A census immediately after the famine in 1851 counted 6,552,385, a drop of almost 1,500,000 in ten years.  Modern historian R.J. Foster estimates that 'at least 775,000 died, mostly through disease, including cholera in the latter stages of the holocaust'. He further notes that 'a recent sophisticated computation estimates excess deaths from 1846 to 1851 as between 1,000,000 and 1,500,000...; after a careful critique of this, other statisticians arrive at a figure of 1,000,000.'  In addition, in excess of one million Irish emigrated to Great Britain, United States, Canada, Australia, and elsewhere, while millions emigrated over following decades.