 Green argued that mystical experience should be characterized in terms of "shared attention", which "occurs when one is engaged in an act of attending to something and in doing so one is consciously coordinating with another on what both will attend to", rather than compared to sense perception.Seigal described "Perceiving God" as a "seminal book".He argued that there is a tension between Alston's thesis "that beliefs about God formed on the basis of mystical perception are prima facie justified" and "a currently popular method for disarming a certain form of the argument from evil".