Is the doorbell there for your (as a householder) convenience or is it a thing to be obeyed?
The doorstep is a bit of an ambiguous place, yes, it's a part of my house but it's also a place where strangers can spend time without your permission. I generally ignore my doorbell to be honest, unless I know it's a man bringing hay or a pre-arranged visitor. So when I walked past my door fully 7 minutes after the doorbell had chimed I didn't really expect to find two people standing there. I then felt obliged to open the door, after all they could see me.
The problem with opening the door to strangers is they have the upper hand, whether it's the postie asking me to take a parcel for the guy next door, whether it's a man telling me how rubbish my driveway is and would I like him to make me a new one or as it was today, people demanding to exchange views on existential matters and the concept of truth. They have the upper hand because they already know what they're going to say, plus they have a leaflet. I, on the other hand, have only a smiling face and the willingness to take in spare parts for a Vauxhall Corsa.
Still, we did have a very nice chat, we're on first name terms (I was so bewildered I even forgot to offer a false name as I usually do in this situation) and they were very lovely and interesting people. I have written some notes on the leaflet as I said I would for when they come back or another chat. On their part I assume they're off to google nihilism. I thought I'd go for that as semantic holism would have lead us to be there all day. I do have all day, don't get me wrong but I just don't think we would have got anywhere.