Sohrab Ahmari’s new book, “The Unbroken Thread,” follows his acclaimed spiritual memoir, “From Fire by Water,” in which the Iranian American journalist had charted the story of his conversion to Catholicism. This book is less personal and more ambitious, laying out an argument that we need to rediscover the traditions that have been swept away by the enhanced focus on individual autonomy and social liberation that has become so prevalent in recent times. In diagnosing what he feels is our civilization’s main malady, Ahmari, opinion editor of the New York Post, speaks from experience. As readers of his previous work will know, Ahmari didn’t convert to Christianity from Islam. Having been raised in a highly Westernized family that fled the Ayatollah’s Iran, the young immigrant embraced a hedonistic lifestyle with a passion and felt appalled that others around the world were denied such freedom. Years on, Ahmari has scaled the heights of …