Both laws by this name can be described as dependent on the activity gradient.  
Solutions to the second law of this name are possible when physically meaningful boundary conditions are specified, and it commonly uses the Gaussian error function in the solution.  This is because it is expressed as a partial differential equation necessary to describe nonsteady state conditions.  Both laws by this name can be described as dependent on the activity gradient.  The first law is relatively simple, being applicable in steady state conditions, and states that flux is proportional to the concentration gradient.  FTP, name these laws analogous to Graham's law and used to describe diffusion.
Solutions to the second law of this name are possible when physically meaningful boundary conditions are specified, and it commonly uses the Gaussian error function in the solution.  
Fick's laws