Even megachurches, with their large and loyal congregations, have come to see the upside of “relevant” marketing, yielding the bizarre spectacle of product placements in sermons. In one of the first such efforts, pastors in 2005 were offered a chance to win $1,000 and a trip to London if they mentioned “The Chronicles of Narnia” during services. For the 2013 release of “Superman: Man of Steel,” pastors were supplied with notes for a sermon titled “Jesus: The Original Superhero.”

Nor are our workplaces and social spheres immune. The time and energy we spend socializing with friends and family has, almost incredibly, been harnessed for marketing, through the business models of Facebook, Instagram and other social media. At the office, the most successful of the productivity-killing distraction engines, BuzzFeed, brags of luring a “bored at work” network hundreds of millions strong.

Unfortunately, there is worse yet to come: The nation’s most talented engineers now apply themselves to making marketing platforms out of innovations — A.I. assistants like the Amazon Echo or self-driving cars. Here the intrusions will be subtle, even disguised, so as not to trip our defenses, but they will be even more powerful, going after our very decision-making processes. Consider how much we already depend on Siri or Google Maps: What happens when our most trusted tools have mixed motives?

Advertising revenue often seems like “free money,” but there are enormous risks for the character of any institution once it begins to rely heavily on advertising income. History and logic suggest that, once advertisers become a major funding source, they create their own priorities, and unless carefully controlled they will warp the underlying space to serve their interests.

This development raises questions beyond the mere issue of how annoying ads can be. The model of individual liberty and a self-reliant citizenry was proposed by the founders and influenced by philosophers like John Stuart Mill, who envisioned sufficient time and space for self-development of character and room for making decisions that are truly ours.

Similar ideas about the prerequisite of free will are to be found in the great spiritual traditions, which sanctify certain times and spaces for the sake of our spiritual development.

These ideals are threatened by a way of doing business that by its nature seeks to invade the most sanctified of spaces.