The answer, of course, is a system based on common courtesy and consideration, mixed with a measure of sheer practicality. In general, women should be invited to precede men, not because this in any way endorses chivalric notions that many may now find awkward or even condescending, but because it provides a totally arbitrary rule that at least minimises the chances of congestion. It may be viewed, then, in the same light as the rule that states one should drive on the left of the road rather than the right. There is no real reason for that: countries in which people drive on the right are in no way different from those where people drive on the left, or, if they are – and they may be – then that is for historical reasons quite unconnected with driving on the left or the right. So the fact that historically women have been invited to go through doors before men provides a basis for a contemporary rule that this should continue to be done.

Unless, of course, the man reaches the door first; in which case he should go through naturally, rather than wait until the woman catches up with him. An exception to this simple, practical rule would be where the person reaching the door first wants to show particular consideration to the other; in such a case the first person should yield to the second person, ushering him or her in with an appropriate gesture. This makes the second person feel better about himself or herself, in that he or she has been shown by the first person to be somebody the first person particularly respects. For this reason, it is a good general rule to allow everybody to go through the door before you. People who do this are usually much appreciated for their manners, but may not get very far in life, owing, perhaps, to the number of doors through which they do not ever pass.

People with obvious infirmities should be allowed to pass through a door before those who are hale; under no circumstances should they be pushed if they take a longer time than usual to pass through the door. Very aged people, those approaching a hundred years of age, should also be allowed through first on the simple, compassionate grounds that there will not be many doors left for them to pass through.