In the case of a cockpit altitude alarm, "pull up from a perilous dive" may not be the appropriate response; "lower your nose and throttle up to build airspeed and get out of a perilous stall" may instead be called for. Additionally, pilots will universally agree that it is worth taking certain actions in order to avoid crashing. Thus, the use of shorthand in that situation is fairly reasonable.

When it comes to declaring what science tells us we "must" do, the picture is far less clear. One reason to be explicit about the difference between "is" and "must" is that even intelligent readers and writers sometimes hold mistaken beliefs here. Another reason is that, even among those in total agreement about the science and in total agreement about certain predictions, there is still disagreement about whether various tradeoffs are "worth" the cost. At that point, science is simply the wrong tool to tell us what we "must" do.