In response to Pat's post, here is how I would distinguish entrepreneurship from speculation in land: 
 
1. If I expect the demand for and price of shoes to rise relative to costs, I would invest in the production of shoes and in the process I would help bring the price of shoes back down close to the costs of production. This is entrepreneurship.
 
2. If I expect the price of land to rise faster than the normal return on other ways that I might invest my money, I would park my savings there. So would other people, and so long as these expectations persist the price of land will continue to increase. Our expenditures do not increase the supply of land, so a rise in its price has no tendency to be reversed through a rise in its supply. This is what makes land unique. Purchases of land -- whether by speculators or entrepreneurs who want it because it is needed to produce shoes or whatever -- are merely transfers of existing title deeds. However, if the price of land is driven up, this increases the land element of entrepreneurs' production costs. These rising costs eat into entrepreneurs' profits. Production will slow, and this weakens entrepreneurs' demand for land. As land prices begin to soften so too would the speculative demand for land. Land values will eventually fall and this will help a recovery of profits on real production, but no thanks to the 'work' of speculators.
 
Speculation in shoes, or gold, or bricks or cement induces an increase in the supply of these things. Speculation in land has no similar effect. A tax on speculative purchases of bricks will harm brick production and keep brick prices high. A tax on land values can have no such effect. On the contrary it would reduce the price of land and encourage land-holding only by those who have a real entrepreneurial use for it as part of the production of real goods and services. 
 
Roger Sandilands