how to edit UI text without Update?

i can only change the ui text within the update. why its not working outside of Update?

using UnityEngine.UI;

private Text score;
private int scoreCount;

private void Start() {
		score = GetComponent<Text> ();
	}

static public void AddPoint() {
        scoreCount++;
		score.text = scoreCount.ToString();
}

i get an error:
error CS0120: An object reference is required to access non-static member

got it