Re: What is your argument against secularism?
I am glad this made you go back and read what I wrote 
You are correct. There is no verse on stoning in Quran. So you were reading!
Similarly, there is no verse on how many Ruku, Sajood, rakaat are there in Salah. So, it means we should do it as we please? Obvisouly No.
The ruling on Stoning (or Rajm in Arabic) was actually revealed but was not made part of Quran by the Prophet (saw) in a narration by Umer (ra). This is same as hadith Qudsi which were also sent down but not made part of Quranic text.
The practice of stoning was carried by the prophet (saw) as is recorded in the history and so was by his companions.