Faced with a task, can you complete it?
Imagine lifting a bag of vegetables onto a shelf. Are you strong enough or tall enough, or will you need to find help?
These are simple enough questions, showing some of the limits to whether you can make the change you want – getting a bag from the floor onto a shelf. Will it possible or impossible? Are there different ways of going about the task, that do make it possible?
All changes are subject to limits: Some changes are possible; some changes are impossible (however you try and go about them).