[2] Pentland argued against the "staples thesis", which posited that Canada developed as it did because of the nature of its staple commodities: raw materials, such as fish, fur, lumber, agricultural products and minerals, that were exported to Britain and the West Indies.
The search for and exploitation of these staples led to the creation of institutions that defined the political culture of the nation and its regions.
This thesis, which was most prominently argued by Pentland's former academic supervisor at the University of Toronto Harold Innis as well as W. A. Mackintosh, was widely accepted during the middle portion of the 20th-century.
"[3] Historian of the Canadian working-class Gregory Kealey argues that "the value of Pentland’s work is located in its break with other existing North American schools of labour studies.
"[4] Kealey also notes that "if Pentland’s Manitoba loyalties were evident in his writings on western labour, his Canadian nationalism also emerges strongly in his last essays.