Some people would agree with this statement because at the end of the day you will have to live with the consequences of your actions, by using other means, your decision may be slanted and you may live to regret it. Only you know yourself best. Another person may agree with this statement down to past experiences. You are the one who has lived your life and only you will have the knowledge of the subject surrounding the decision that you need to make. You have made decisions in the past so surely you know the best potential one for future ones. Some people may agree with this and say that holy books are out dated or don’t have relevant information for every situation. The holy books where written down hundreds of years ago when the world was very different from what it is now, the things that were morally accepted in the past may not be now, so by using a holy book instead of your conscience to make a moral decision you may be taking the wrong path into an old fashioned dilemma. As for situation relevance, the holy books aren’t going to have an answer to every single moral decision you face. If a holy book does contain a similar situation to the one that you are faced with, it still won’t be exactly the same and is most likely to not end with the same consequences therefore conscience would be a better guide.
Some people would disagree with this statement if they were religious because by using just your conscience you may not be following the guidelines within your religion or fulfilling the purpose God has for you. If you souly make a decision with a conscience you may be choosing something which you may live to regret, especially if you are a naïve person. By using holy books you are widening your knowledge and wisdom of how to make a decision and therefore you will make the right ones in the future. Another reason why people may disagree with this statement is due