The aim of my dissertation is to show what an adaptive explanation is and to draw a conclusion on the example of incest whether the adaptive explanation is good in its definition of incest avoidance. The paper presents a discussion of the explanation within which there is a division into scientific explanation. Within the scientific explanation are Hempel's "Covering law theory," the D-N model (with Oppenheim in 1948), the I-S model, the unificationist, causal-mechanical model, and the adaptationist explanation. The simplest definition of a scientific explanation is: to questions that contain why, a scientific explanation answers us with why. An adaptationist explanation is an explanation based on evolution and natural selection, and with their help it provides us with answers to our questions. In the case of my example, the adaptationist explanation explains why we avoid incest. In the adaptationist explanation, I will talk about the discussion between adaptationists and pluralists, and I will continue to focus on the adaptationist explanation within sociobiology and evolutionary psychology. I will present their explanation which explains to us the avoidance of incest. The emphasis is on Westermark's hypothesis, which is predominantly sociobiological, but also important in psychology. However, evolutionary psychology introduces some novelties in relation to sociobiology, which is why they differ. In addition to presenting explanations, I will also cite criticisms of the same. To meet my goal, it is important to cite criticisms as well so that I can judge whether adaptive explanations are good when it comes to avoiding incest or not.