The phrase "incalculable harm" means a great amount of damage or negative effects that are difficult or impossible to measure or predict. Full definition
More fundamental are problems which human beings have always faced when trying to shape their future — only now these problems bode incalculable harm because of the growth in population, and the growth in power of technology. (religion-online.org)
What seemed to them, in a cloud of missionary zeal, like a good idea (frankly, they could not be reasoned with, nor were they interested in evidence, history, human nature, or logic) turned out to a harmful, failed philosophy that, if adopted, would have wreaked incalculable harm, not only on their own nations, but on the whole World. (slaw.ca)
Nearly two decades later, I'm still chastened by the book's central lesson: A government policy developed by mostly benevolent leaders hoping to improve the lives of the disadvantaged — in this case, by razing old, low - income, ostensibly decaying neighborhoods in favor of gigantic public - housing skyscrapers — did incalculable harm to those it was designed to help. (educationnext.org)