Background. This study dealt with the question whether abstract concepts and rules can be directly taught or can only be explained by using examples. The issue, known as Meno's Paradox, was addressed in the context of understanding expository texts. Aims. We set out to show the indispensability of examples in the process of acquiring knowledge of concepts and rules. By blocking any possibility of linking concepts to examples we hoped to show the understanding of abstract concepts is impossible without a concrete context of interpretation. Samples. In two experiments, secondary school students (17 years of age) and undergraduate university students were asked to study expository texts with no examples or with many examples. Methods. In Experiment I, two existing texts were manipulated by either adding examples or replacing specific concepts by more ambiguous concepts. In Experiment 2, two expository texts (one with rules, one with examples) on the law of large numbers were developed. Apart from that, a questionnaire to assess students' habit of concrete elaboration whilst studying expository texts was administered. Results. Experiment I revealed that an expository text with ambiguous terms is difficult to understand. This evidence supported our claim that a concrete context of interpretation is indispensable. However, there was no difference in understanding of texts with many or few examples. An explanation might be that students were able to think of relevant examples themselves. Evidence for this active way of text comprehension was found in Experiment 2. An interaction between content (abstract, concrete) and learning style (high or low on concrete elaboration) showed up. Students high on concrete elaboration understood the abstract text better than students low on concrete elaboration. The reverse held for the concrete text. Conclusion. So, support was found for the indispensability of concrete examples, which should be available in the reader's memory or provided in the text.