In normal life situations there is always the possibility that something will get in the way of logic working perfectly. We might think that, logically, one plus one is always two, but in real life some aspect of the objects in question might get in the way. If someone gives you one cookie and then another cookie you might have two cookies but it depends if you ate them. If you had one flower and you buy another then you might have two, but perhaps you bought another because the first one died.
Abstraction is the process of deciding on some details to ignore in order to ensure that our logic does work perfectly.
-Eugenia Cheng, The Joy of Abstraction