However, Cleanthes has an opening for reply here. Newton, for instance, observed gravitational effects in one small corner of the universe (earth) and from there drew conclusions about the entire universe. The same can be said about all of the scientific conclusions that have been drawn about the nature of matter and the properties of light: scientists only observed light and matter in one small corner of the universe, but they claim to thus reach knowledge about all matter and light. Scientific reasoning, then, seems to engage in the same form of "mistake" that Cleanthes engages in. Scientists constantly extrapolate from the evidence they find in their small corner of the world. Given that this sort of reasoning is standard in science, it seems difficult to fault Cleanthes for engaging in it.