We have to make choices every day, and a lot of them are connected with what to believe in, what to accept as knowledge, or whom to trust. Most of us need some basic truths to base our lives upon. Inevitably, we have to determine whether something is true or false. Sometimes these choices seem obvious and some assertions- self-evident truths. In other occasions, on the contrary, the choice is much harder to make. The choice between accepting something as true or denying it and the certainty that we have in making this choice are dependant on numerous factors.These factors can generally be divided in two large groups- rational and irrational factors. In other words, sometimes we can grant logical proof and valid arguments for regarding something as true; in another time, we can accept something as true even without any rational proof. It seems that it should be easy to distinguish true and false with these numerous criterions available. In this essay, I will focus on the reasons why in the reality the choice between true and false is often made with many difficulties.There are several types of rational proof, or at least, what different people may consider rational. These include scientific proof, opinions of authorities, logical reasoning, own (or borrowed) experiences and reliable sources of information.Scientific proof is traditionally considered a very relevant criterion in deciding over true and false. We usually deem- if something is proved using science, it must be true- as simple as that. However, scientific proof can be hastily formed or based on incomplete information or incorrect research, and there are numerous cases in history when scientific proof has been unreliable. For example, for many centuries, people believed that the earth is flat and that mice originate from dirty laundry. Today we recognize that what they considered scientific proof, was simply irrelevant, but this makes us realize how short=lived scientific proof may be over time.Opinions of authorities is one more criterion that might deem reliable at the first glance. But there are two types of authorities- they may be real professionals, or simply people we trust. The second type of authorities is doubtable- anyone can use our trust to make us believe in what is actually false (for example, during the World War 2, millions believed in whatever Hitler had to say, just because those were the words of the leader). Professionals are more credible, but they, too, make mistakes in their own fields. An example is Aristotle- even though he was an eminent philosopher and the first recognized physician, he believed that the Earth is flat- just like anyone else at that time.Additionally, it is not always so easy to say whether somebody deserves to be an authority or not.Logical reasoning should give satisfying results, but it is hard to assure it really is logical- because of the widespread logical fallacies. A very common fallacy occurs when we hastily draw conclusions from facts that are appropriate, but insufficient. For example, last summer we used a chemical that should destroy ants in our summerhouse. We used the whole aerosol but there were no results; it was enough a fact for my mother to draw a conclusion that this particular pesticide brand is useless. However, later I checked the expiry date. It had passed two years ago. So we bought a new bottle of spray, and this time, ants were gone for good. This shows how insufficient facts can lead to false conclusions.Most of us trust in our experiences when making decisions. It is clear that others’ experiences might be misleading- even if they are not deliberately deceiving us, their experiences may lead us to false conclusions just like our own. We might have seen rain in all the summer solstices that we remember; however, it is not enough to form a statement “summer solstice is always rainy”, because we simply haven’t seen all solstices. Experience alone is rarely enough to distinguish true and false, using it, it is likely to get into logical fallacies.When mentioning reliable sources of information, the first question is- which sources are reliable, then? Critically thinking, we have to admit that there are no sources that are 100% reliable. It is similar as with experiences of others- even if we are not lied to, we cannot trust others, for we cannot completely trust ourselves. Even equipment can be unreliable- all tools and machines can be faulty, even computers. For example, signalisation may also not go off; radars can miss an enemy plane with a special protection, and so on. Even when the calculations we make are correct and should lead us to a true result, in the real life (apart from mathematical exercises) we cannot be sure of accuracy of the data that we process.We may be capable of performing calculations about reality, but we cannot perceive reality in a certainly “true” way. That is in fact the greatest deficiency of these logical criterions according to which we attempt to distinguish true and false. Our sight, hearing and other senses may deceive us.Another type of criterions of distinguishing true and false are irrational (or subjective) ones. These include emotions, stereotypes and biases, pseudosciences, religion and faith, and intuition.Emotions are a factor that commonly contradicts with our logical judging. When it is hard to accept something as true, our emotions can make us neglect any sensible arguments. For example, a wife may have plenty of proof that her husband cheats on her, at least enough to start doubting his sincerity (blonde hairs on his suit occasionally, late working hours, workshops in weekends), but her feelings towards her husband will make her ignore any evidence, opposing it with a sole, irrational statement- “I know he loves me”.Stereotypes and biases form another illogical influence over our judgements. I this case, we often seem to need no arguments at all to regard something as true; instead, something is accepted as true without any investigation, and, when a person is asked to prove why a stereotype is true, his arguments are illogical and absurd. For example, if a child is brought up in a racist family, he is likely to uphold discrimination of other races without any arguments. For him, statement “all Asians are inferior” will seem true without any proof.Pseudosciences (astrology, phrenology and others) may seem entirely true to someone. Still, they cannot fully be supported (or argued) with facts, which makes them irrational. These are more like beliefsReligion and faith make up another illogical factor affecting our resolutions. An appropriate example is middle Ages when people kept on believing that Earth is the centre of Universe, because the Bible told them so. Here we can include not only religion, but blind faith as well. Both of them usually not only need no logical arguments to support any confidences, but also block any valid arguments that oppose these convictions. An example is Middle Ages, when Catholic Church refused to accept that the Earth is round and tired to silence anyone who could prove the opposite.Intuition (and other such things- like sixth sense or extrasensory perception) is another way of giving us unreasonable judgements of true and false. It differs from the other irrational criterions by being supernatural- only some believe in these things and even fewer deem to have the ability to use these “powers”. It is a controversial point of whether we can trust them or no, and attitudes towards them are very different, but it is clear that they have nothing to do with logics.It is clear that these irrational criterions may sometimes be determinant, but not very reliable components in deciding what is true or false. That is why they often create a lot of difficulties to approach the world reasonably and logically and form true knowledge.The rational factors that were discussed earlier are more reliable, but then again, as it was shown, even if we judge logically and process the obtained information rationally, there is no guarantee that the information itself is entirely true. That is why it is extremely difficult to form unquestionably TRUE knowledge or to distinguish true and false. Even if our mind is processing the facts and other information correctly, our perception and other ways of knowing can prove deceitful; often different ways of knowing and areas of knowledge can give us contradicting information. Every source of knowledge can turn out unreliable.