How can it be claimed that the penal laws of the Qur'an are practicable ?

Any penal law can be said to be practicable if it exhibits the following qualities:

1. It becomes a retribution for the crime committed.

2. It prevents crime.

3. It serves to create a sense of dread in criminals.

4. It serves to assuage the feelings of the victims  who have undergone  privations.

5. It seeks to refine and transform the criminal.

6. It provides for the compensation of those who suffered losses due to the crime.

7. It seeks to make the criminal repent his deed.

8. It seeks to protect the society from crime and disorder.

All of these qualitative functions may be seen to be fulfilled by any of the penal laws in Islam. It can thus be said without a shadow of  doubt, that they are, indeed, practicable.