  In a stochastic process, where noise is always present, the
fluctuation-dissipation theorem (FDT) becomes one of the most important tools
in statistical mechanics and, consequently, it appears everywhere. Its major
utility is to provide a simple response to study certain processes in solids
and fluids. However, in many situations we are not talking about a FDT, but
about the noise intensity. For example, noise has enormous importance in
diffusion and growth phenomena. Although we have an explicit FDT for diffusion
phenomena, we do not have one for growth processes where we have a noise
intensity. We show that there is a hidden FDT for the growth phenomenon,
similar to the diffusive one. Moreover, we show that growth with correlated
noise presents as well a similar form of FDT. We also call attention to the
hierarchy within the theorems of statistical mechanics and how this explains
the violation of the FDT in some phenomena.
