I am going through Groenewold's theorem and in his book: On The Principles of Elementary Quantum Mechanics, page 8, eq. 1.30:

> 
> $$[\mathbf{p}, \mathbf{q}]=1\left(\text { i.e. } \mathbf{p
>  q}-\mathbf{q} \mathbf{p}=\frac{\hbar}{i}\right),\tag{1.30} $$
> 
> 
> 

and he wrote: 

> 
> The classical quantities $a(p,q)$ can be regarded as approximations
>  to the quantum Operators $\mathbf{a}$ for $\lim \hbar \rightarrow 0$.
> 
> 
> 

How did he assume that $\frac{\hbar}{i}=1$? And if $\hbar$ (as we have learned it) is a constant and it is precisly equal to $6.5821 × 10^{-16} eV s$, how can we say that it goes to zero?