The U.S. Supreme Court’s landmark decision protecting cellphone privacy sent a strong signal on Wednesday that the admittedly low-tech justices grasp the profound changes that the Information Age has wrought.

“Modern cell phones are not just another technological convenience. With all they contain and all they may reveal, they hold for many Americans ‘the privacies of life,’ ” Chief Justice John Roberts Jr. wrote for the court. He added that cellphones and smartphones are “now such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy.”