The aiding and abetting theory of liability is referred to as "concert of action." Juhl v. Airington, 936 S.W.2d 640, 643 (Tex. 1996).
The supreme court has noted "whether such a theory of liability is recognized in Texas is an open question." Id.
In Juhl, the court set out two descriptions of the theory, one by Prosser and Keeton and the other from the Restatement (Second of Torts). Juhl, 936 S.W.2d at 643.
Prosser and Keeton describe the concert of action theory as follows:
"All those who, in pursuance of a common plan or design to commit a tortious act, actively take part in it, or further it by cooperation or request, or who lend aid or encouragement to the wrongdoer, or ratify and adopt the wrongdoer's acts done for their benefit, are equally liable." Id. (quoting W. Page Keeton and D. Owen, Prosser and Keeton on the Law Of Torts § 46, at 323 (5th ed. 1984)).
The Restatement provides liability can be imposed on a person for the conduct of another that causes harm if the defendant:
(a) does a tortious act in concert with the other or pursuant to a common design with him, or
(b) knows that the other's conduct constitutes a breach of duty and gives substantial assistance or encouragement to the other so to conduct himself, or
(c) gives substantial assistance to the other in accomplishing a tortious result and his own conduct, separately considered, constitutes a breach of duty to the third person. Id. (quoting Restatement (Second) of Torts § 876 (1977)).
The Juhl court stated, "if we were to adopt § 876(a) we would require allegations of specific intent, or perhaps at least gross negligence, to state a cause of action." Juhl, 936 S.W.2d at 644.
Specific intent requires an agreement to accomplish an unlawful purpose or to accomplish a lawful purpose by unlawful means; neither proof of negligence nor proof of intent to engage in the conduct that resulted in the injury is enough. See id.