Ijtehad in tashayyu: A further analysis

Further to what was discussed in the earlier post, ( Ijtehad in sharia allowed? ), in which we it was shown that the term ijtehad has not been used in ahadith and our classical scholars such as Shaikh Tusi have condemned ijtehad; we will now take a look at the technical definition of ijtehad as provided by some of our greatest scholars.Muhammad Ibrahim Jannati says in his book, "Ijtihad: Its Meaning, Sources, Beginnings and the Practice of Ra'y":

"(f) The great mujtahid al‑`Allamah al‑Hilli (648‑726/1250‑1325), in his work al Nihayah on usul al‑fiqh, writes: Ijtihad means employ­ment of effort for arriving at presumption with regard to a hukm of the Shari ah, in a way that is not blameworthy on account of negligence or omission.

(g) Al‑`Allamah al Turayhi says: Ijtihad is to employ one's effort and endeavour in pursuit of some difficult task and for arriving at pre­sumption with regard to a hukm of the Shari`ah. 

(h) The Usuli mujtahid al‑`Amili al‑Jiba`i says: Ijtihad is the effort and endeavour of a faqih in order to arrive at presumption in regard to a hukm of the Shari`ah. 

(i) Al‑Shaykh al‑Baha i in his Zubdah quotes al‑Hajibi to the ef­fect that: By ijtihad is meant the exhaustive efforts of a faqih for ar­riving at presumption in regard to a hukm of the Shari’ah. Al‑`Allamah al‑Hilli agrees with this definition in his book Tahdhib al‑‘usul."

http://www.al-islam.org/al-tawhid/ijtihad/1.htm#6
    

So is this practice valid? What do ahadith say?   

Kafi
محمد بن يحيى، عن أحمد بن محمد، عن الوشاء، عن مثنى الحناط، عن أبي بصير قال: قلت لابي عبدالله (عليه السلام): ترد علينا أشياء ليس نعرفها في كتاب الله ولا سنة فننظر فيها؟ فقال: لا، أما إنك إن أصبت لم تؤجر، وإن أخطأت كذبت على الله عز وجل
Muhammd b.Yahya, from Ahmad b.Muhammad, from al Washa', from Muthnal Hanaat, from Abi Baseer said: (I) said to Abi Abdullah(as) "Things (religious questions) are referred upon us (which) we do not recognize (find) in book of Allah (swt) or sunnah so we look/speculate into it (for answer). (Imam(as)) said "No, if you hit(the mark) you'll get no reward, and if you made mistake then you lied upon Allah (swt)."   

Grading

Majlisi (Miratul uqul): حسن Hasan (Good) 

Bahboodi: صحيح Sahih (Correct/Authentic) 
    

Kafi 
علي بن إبراهيم، عن هارون بن مسلم، عن مسعدة بن صدقة قال: حدثني جعفر، عن أبيه (عليهما السلام) أن عليا صلوات الله عليه قال: من نصب نفسه للقياس لم يزل دهره في التباس، ومن دان الله بالرأي لم يزل دهره في ارتماس، قال: وقال أبوجعفر (عليه السلام): من أفتى الناس برأيه فقد دان الله بما لا يعلم، ومن دان الله بما لا يعلم فقد ضاد الله حيث احل وحرم فيما لا يعلم
 Ali b. Ibrahim, from Haroon b. Muslim, from Mas'adah b. Sadaqah who said: Told me Ja'far(as) from his(as) father(as) that Ali(as) said: "Whoever inflicted upon himself of the qiyas (analogy), his lifetime (would be spent) in confusion, and whoever practiced religion of Allah(swt) with ra'y (opinion, presumption etc), his lifetime (would be spent) in a drowned state." (Narrator) said: Abu Ja'far(as) said: "Whoever gives fatwa to people by ra'y then certainly he practiced religion of Allah(swt) with what he did not know, so indeed he opposed Allah where he made halal and haram in what he did not know."