To think correctly, any normal person needs to comprehend the truth. And the question of what is the truth worries people the most. As soon as you try to find the truth, everything happens as always. You ask to bring something tasty, and they slip you some rubbish, like palm oil, only someone's opinion acts as "palm oil." And it is foolish to argue about opinions. But does such an opinion imply a rejection of knowledge? This book will help to deal with subtle philosophical concepts and the role that dialectics, logic and controversy play in the modern world.