Unique = Necessary or Sufficient?

[LauraS737]

Hello,

If something is unique to a certain place/person/animal/etc., does that mean that that something is a necessary condition? OR is it a sufficient condition? Can someone explain in detail, please?

Thanks!

[andrewgong01]

Hello,

If something is unique to a certain place/person/animal/etc., does that mean that that something is a necessary condition? OR is it a sufficient condition? Can someone explain in detail, please?

Thanks!

I think it would be sufficient if this thing is unique.

Uber is unique only to people with smartphones since you need a smartphone to use the app. Hence if you use Uber I know that you have a smart phone. However, knowing you have a smartphone does not allow me to say you use Uber (if it was the case that unique gives us a necessary condition). In other words, using Uber is not a necessary condition everyone must do in order to own a smartphone as many people own a smartphone without ever having used Uber. Hence this unique something is sufficient for us to conclude something (you have a smartphone) but is not a necessary condition for the "certain place/person/animal etc"