 A similar point holds for the theory of knowledge where it is generally held that if I know that p, then p is true (see the entry on  the analysis of knowledge).  The truth of p is a necessary condition of knowing that p, according to such accounts. In saying this we do not rule out claims stronger than simply saying that the truth of p follows from the fact that we know that p. That a belief is true—for example—may be (part of) a reason for thinking it constitutes knowledge. Other cases involve inferences licensed by physics, biology and the natural sciences—inferences that will involve causal or nomic conditions. Again there is need for care in determining whether reason why or reason for thinking relations are being stated. The increase of mean kinetic energy of its molecules does not just imply that the temperature of a gas is rising but also provides a reason why the temperature is increasing. However, if temperature is just one way of measuring mean molecular kinetic energy, then a change in temperature will be a reason for thinking that mean kinetic energy of molecules has changed, not a reason why it has changed.