“不能从静态上下文中引用非静态方法"背后的原因是什么?

非常常见的初学者错误是当您尝试静态地"使用类属性时无需创建该类的实例.它给您留下了提到的错误消息:

The very common beginner mistake is when you try to use a class property "statically" without making an instance of that class. It leaves you with the mentioned error message:

您可以使非静态方法成为静态方法，也可以使该类的实例使用其属性.

You can either make the non static method static or make an instance of that class to use its properties.

这背后的原因是什么?我不关心解决方案，而关心原因.

private java.util.List<String> someMethod(){
    /* Some Code */
    return someList;            
}

public static void main(String[] strArgs){          
     // The following statement causes the error. 
    java.util.List<String> someList = someMethod();         
}