java ，为什么无法从静态上下文中引用非静态方法?

Question

public class TextLinearSearch{
   int[] list={1,4,2,5,-3,6,2};
   public static void main(String args[]){
  linearSearch(list,-3);
  }
   private void linearSearch(int[] list,int key){
    for(int i=0;i<list.length;i++){
   if(key==list[i])
System.out.println(i);
}
   System.out.println("There is no right number in the list");
  }
}