Understanding SUFFICIENT/NECESSARY conditions and their relationship

ObjectionQuarantined

Hi everyone, hope your studies are going well. I just wanted to share an explanation of SUFFICIENT and NECESSARY conditions. This explanation is something I randomly came up with and I hope it works for someone trying to understand how that works in LAWGIC.

Explanation of the Sufficient/Necessary condition:

I want you to imagine that you are trying to enter into the most secure building on earth. There is only one way into the building, and that’s through a giant electronic glass door.

Conditions:
YOU are on the outside.
YOU have a proximity card that can be scanned to open the door
There is also a buzzer outside the door that you can ring.
When you do ring the buzzer, the door can be opened on the inside by a SECURITY guard.
Some days your proximity card works and some days it does not. Depending on if you are needed in the building on that day.

So there we have it.

Now:

SUFFICIENT: You scan your proximity card OR you ring the buzzer.
NECESSARY: The door opens

Scenario one:

1. Sufficient occurs ------> Necessary occurs (You scan your proximity card on the day you’re authorized to enter the building and immediately that door opens. Your card is sufficient to open it)
2. Sufficient occurs ---> Necessary occurs (You arrive at the door and realize, you’ve forgotten your card. So you hit that buzzer and the guard presses the button. The door immediately opens. The guard pressing that button is sufficient to open the door)
3. Sufficient fails ----> Necessary unaffected ( You arrive at the door on the day of work. One of two things happen. You lose your card. Well, the door could still open! Security guard could open it, another person walking behind you can open the door, someone leaving the building etc. the same can be the case if the security guard fails to open the door. You can have your key or someone else can open it.)
4. Necessary occurs ---->  Sufficient irrelevant or falls off (You get to the door on the morning you’re suppose to work, and while fumbling around in your pocket for your proximity card. You notice the door is open. At this point, The NECESSARY thing you need to enter the building, has happened. You don’t care about scanning your card or hitting that buzzer. You can still do it, but you don't have to.)
5. Necessary fails ----> Sufficient fails (Now for whatever reason, one morning you walk to that door and that door does not open at all. What do you know? What do we all know? Well we all know that:
   a. The necessary thing you needed to enter the building: DOOR OPENING, has failed.
   b. If that door failed to open what else do we know? Well, your card didn’t work or the guard was just not going to let you in that morning. IN short, door didn’t open. Thus all the things that could’ve made it open... someone walking ahead of you or leaving the building or using your card or the guard pressing the buzzer didn’t happen. )

I really hope this helps. It's lengthy but I imagine it would be much simpler as a short cartoon.