It is difficult to share values and aims in the contemporary society, which is abackground of the difficulties of consensus building. The purpose of this paper isto consider the location of problems concerning the difficulties by referring toprevious researches on risks. Theories of Ulrich Beck, Slavoj Žižek and NiklasLuhmann will mainly be focused on.Beck is well known to his theory of risk society. He says that expert knowledgeis necessary to recognize risks in the contemporary situation, which is a result ofthe radicalization of modernity. A main character of a risk society is uncertainty.For example, not only the lay but also experts cannot predict the effects of theproblems caused by science and technology such as environmental problems.People share anxiety and seek safety, but it will not motivate them to change thesituation because their main interest is to avoid the worst. Moreover, the more thesituation becomes serious, the more they will be faced with what they do notknow. In spite of this paradoxical matter, they have to make a decision to avoidthe worst.Žižek’s thought is based on Lacanian psychoanalysis. He tries to explainwhere the problems are in a risk society from the view of the structure of thepsychoanalytic subject. The imaginary is stable as long as the symbolic orderworks well. However, this function tends to become unstable in the contemporarysituation. Traditional values and ethics are not self-evident today because of therapid development of science and technology. Ethics committees are organized every time problems occur, but they cannot recover the obviousness of socialvalues. The disintegration of the symbolic order is a result of the radicalization ofreflexivity. The obviousness relies on non-reflexive acceptance of the symbolicinstitution.Luhmann distinguishes risks from dangers. Risks are the losses which arerecognized as the results of decisions, and dangers are the ones which arerecognized as what are provided from the outside. There is a gulf between risksand dangers, in other words, between the decision makers and those affected. Forexample, the decision makers may communicate with those affected. Even if theysucceed in building a consensus as a result of this communication, the structure ofthe conflicts among them itself continues to exist in the concerned society. It isusually said that communication, participation, ethics, and so on are importantelements when they try to build a consensus, but none of them can bridge the gap.Obviously these three theories have different premises and major concerns,though all of them try to analyze the problems of consensus building. It will bedifficult to bridge among them, but comparing their premises and major concernsis significant. Their characters and efficiency are clarified to some degree throughthis research. Knowing characters and efficiency of some theories is necessary inapproaching complex problems in the contemporary risk society, becauseexamining the various aspects is a key to grasp the entire image even if it may betentative.