Knowledge is often defined as being a justified true belief but it is hard to find the moment when we can consider our beliefs to have enough justification to be true.
The evidence which we use to justify our beliefs in ethics, mathematics and natural sciences, are all different. Therefore the knowledge we claim to be true in each of the areas is a different kind of knowledge and has different certainty. In mathematics all truth is based on certain laws and for as long as we can guarantee that these laws are right, everything we know is right.
For example, we know that the corners of a right-angled triangle add up to 180 degrees and because of that we can say that a rectangle’s corners add up to 360 degrees. Knowing that, we can build houses, planes and other machines. We can say that most of our knowledge in maths is true because it all coheres with our fundamental beliefs about maths and with what we know about real life. On the other hand, we keep discovering new things, which require new and improved mathematical theories.Although we are certain that three sides of a triangle add up to 180 degrees on a 2 dimensional area, we now know that this is not the case with three dimensions.
Similarly, all mathematical laws that apply to our universe, it is probable that in another universe completely different rules would apply. It would be arrogant to say that everything we know in maths is certain because we keep making new discoveries, which make us amend our previous laws. We can be fairly certain that we all see the same things and the fact that mathematical truths apply to real life, makes truth in mathematics fairly certain.For example, we use statistics to find how big the percentages of occurrences in real life are and we have enough evidence to back that up in real life. We have the justification to believe that something is the way it is and also the proof in real life examples.
It would be reasonable to assume that since human sciences are something that is closer to us, we would be more certain of the truth we can find there. Psychology, sociology and economics are all sciences which we have a lot of contact with in everyday life. We talk with people every day and to do that successfully, we have to know some psychological truths.We can be very certain in social aspects that we have experienced ourselves.
For example, we know that people can’t be happy and very hungry at the same time. Still, the fact that the same patterns occur, doesn’t mean that we wouldn’t find one person who would act differently from the rest. For this reason, we can’t also predict the behaviour of large groups of people. For example, usually when inflation is high, unemployment is low because people have more reason to invest in employing new people. However, this is not always the case although the probability of that happening is big.There are areas in social sciences which can’t be summarized by certain laws of behaviour. For example, we can’t say that we know that most people will pick cherry-flavoured ice-cream instead of a chocolate one because we don’t have enough justification to think that. If we made a survey amongst thousands of people and all of them would prefer cherry ice-cream, we would have reason to believe that there is a reason behind the preferences of all people, but we can’t make that a universal law until we know what the justification behind the tendency is.
One could say that truth in ethics could also be found by analysing the behaviour of large groups of people. It would be sensible to think that if something would be ethically right, it is considered to be ethically right with a large group of people because all these people can’t be wrong. For example, the whole society thinks that hurting someone unnecessarily is unethical. This means that there has to be a universal truth to that because everyone thinks like that and this makes the knowledge in ethics reliable.On the other hand it could be asked whether we should judge the certainty of knowledge in ethics by the amount of people who believe that certain ways of behaviour are right. A few centuries ago the whole society believed that it is right to kill women with red hair because they were thought to be witches and just two decades ago gay people were considered to be immoral by a large part of the society. Therefore, ethical knowledge is not only about the moral of the society and the truth in ethics is harder to find.Perhaps true knowledge in ethics can only be found in doing what one has thought through and not always accepting all the society’s truths.
If people would have been more willing to step up to protect gay people ten years ago, a lot of lives would be different. We can find what is moral and immoral by basing our decisions on our personal experience and making a conclusion by thinking things through with our own head. The problem with that kind of thinking is that this way there can’t be any moral truths because often people come to different conclusions even when they have had the same experiences before.For example, two people who have been picked on at school might have different ideas about whether it is moral to stand up to protect someone in the same situation. Truth in ethics is not certain because two different people can make different ethical judgements.
Furthermore, if we can’t agree on certain ethical truths, perhaps no absolute truths in ethics and we can never obtain true knowledge in ethics. Still, time has shown that over time, people do agree on certain beliefs. We have other ideas now than we had a century ago because we know about other areas of knowledge.We all agree that we have made some kind of development because if we would know better, we wouldn’t act the way we do now. The truth in different areas of knowledge is very different. In maths, all what we know is based on our observation about the world.
The reliability of that source is very limited because we know that the area which we are able to explore is very little compared to the complete area to be discovered.. We can be fairly sure that we all perceive the same things in the world but we cannot be certain of the way people think because we have no insight into that matter.
Although we can make some very accurate predictions about human behaviour, we do not have a lot of evidence to claim anything about the whole society. Ethical truths can be found by using reason but we can’t be certain that all those truths apply to the whole world because our way of thinking is limited and every person has a different way of thinking.