Everything a person needs to avoid real harm, they have placed within him. If it doesn't harm your character, how can it harm your life? Nature would not have overlooked such dangers through failing to recognize them or because it saw them but was powerless to prevent or correct them. And i think it's at this point, especially that last sentence, where we return to what marcus frequently wanting to convey to us. We as humans have all the necessary logical and disciplinary resources to avoid or absorb harm in a helpful way.