Abetment may be committed in various ways enumerated in Sections 107 and 108 and conspiracy is one of them. In the next place abetment per se is not a substantive offence, while criminal conspiracy is a substantive offence by itself and is punishable as such.
Difference between Sections 34, 107, 109 and 120-A:
Section 34 embodies the principle of joint liability in the doing of a criminal act, the essence of that liability being the existence of a common intention. Participation in the commission of the offence in furtherance of the common intention invites its application.
Section 109, on the other hand, may be attracted even if the abettor is not present when the offence abetted is committed provided that he has instigated the commission of the offence or has engaged with one or more other persons in a conspiracy to commit an offence and pursuant to the conspiracy some act or illegal omission takes place or has intentionally aided the commission of an offence by an act or illegal omission. Criminal conspiracy, as defined in Section 120-A, differs from other offences. In that mere agreement is made an offence even if no step is taken to carry out that agreement.
Though there is close association of conspiracy with incitement and abetment the substantive offence of criminal conspiracy is somewhat wider in amplitude than abetment by conspiracy as contemplated by S. 107, I.P.C. A conspiracy from its very nature is generally hatched in secret.
It is, therefore, extremely rare that direct evidence in proof of conspiracy can be forthcoming from wholly disinterested quarter or from utter strangers. But, like other offences, criminal conspiracy can be proved by circumstantial evidence. Indeed, in most cases proof of conspiracy is largely inferential though the inference must be founded on solid facts.
Surrounding circumstances and antecedent anil subsequent conduct, among other factors, constitute relevant material. In fact because of the difficulties in having direct evidence of criminal conspiracy, once reasonable ground is shown for believing that two or more persons having conspired to commit an offence then anything done by anyone of them in reference to their common intention after the same is entertained becomes, according to the law of evidence, relevant for proving both conspiracy and the offences committed pursuant thereto. (N.M.M.Y. Momin v. State of Maharashtra, A.I.R. 1971 S.C. 885, 886).