The discussion focuses on understanding the concept of half-life in nuclear decay and its relationship to probability. It explains that the activity of a radioactive substance is proportional to the number of atoms present, allowing for calculations of the remaining quantity over time. The half-life is defined as the time required for the quantity of atoms to reduce to half its initial value. The conversation also clarifies that half-life is an independent process, unlike the outcomes of rolling dice, which are independent events. Finally, it mentions the application of carbon dating for determining the age of materials, noting its limitations for very old samples.