What are the prerequisites for great new scientific ideas? Intelligence and creativity? Assuming these two variables-feel free to add more if you wish-does the mind ever peak at a certain age in either of these two areas, be it physically or simply subjectively? It seems the true geniuses do their great work in their 20s. Assuming Einstein took an interest in physics in his 30s or even 40s or 50s could he have done the same things he did?