In arguing that “reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them,” the British (actually, Scottish, an important distinction for those of Scottish heritage) philosopher David Hume (1711-1776) was advancing his seminal theory that human decision-making cannot be divorced from the underlying emotions and prejudices that people bring to any given issue. While Hume could be said to have overstated his case significantly – after all, cognizance of one’s preexisting beliefs can mitigate the influence those beliefs have on decisions – his contribution to the advancement of modern thought cannot be overstated. In advancing his argument, however, he was simply drawing attention to what he believed was the fallacy advanced by others that reason could be separated from emotions and that man could act in objective self-interest. In short, he was simply pointing out what many political theorists have subsequently noted in the degree to which personal experience and biases cannot be divorced from the mental process by which one processes information and derives conclusions.
In stating his theories of human thought, Hume was not ignoring the intentions of people to act morally or rationally; rather, he was emphasizing the importance of taking emotions into account when attempting to understand the thinking of others. In writing that “a wise man proportions his belief to the evidence,” he was illuminating the dearth of appreciation among his fellow scholars for the role that preexisting beliefs play in how one views the actions or statements of others. In his Treatise of Human Nature, Hume wrote that,
“For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never catch myself at any time without a perception, and never can observe anything but the perception.”
People approach topics or events from different perspectives. They view developments or listen to arguments through their own unique prisms evolved through their individual experiences and conceptions. All Hume is suggesting in his oft-cited quote is that it is disingenuous to suggest that cold-blooded calculations absent emotional preconceptions account for the manner in which people make decisions. Recognition of that fundamental truth is the key to diminishing its significance.