(concurring). Although I concur in the judgment of the court, I am unable to join in that part of the majority’s opinion that purports to create use immunity that would prohibit testimony in one criminal case from use against the witness in another criminal case.
As the majority correctly notes, Neely never did testify in this case to matters that would incriminate him in the pending Milwaukee case charging him with armed robbery. Because it addresses an issue that is unnecessary to the determination of this case,1 the opinion is advisory on the subject of use immunity. In plowing new ground unnecessarily, the majority embarks upon advice to the bench and bar with respect to a restrictive interpretation of waiver of the privilege against self-incrimination.
The weakness of this advisory opinion is apparent because it lacks the underpinning of a factual basis. Absent a factual basis, the ratio decidendi of the opinion offers a little prospect for reasoned growth and development because it lacks a foundation and structure that *334furthers analysis.2 For example, the opinion does not answer these questions about the use immunity that the majority purports to establish:
1. Is use immunity available to any witness or only an accused?
2. Is use immunity grounded upon a principle of waiver in interpreting evidentiary principles or is it a principle of constitutional dimension ?
3. Is use immunity a due process right to present a defense or an implementation of the fifth amendment privilege against self-incrimination?
4. What will be the effect of use immunity upon the confrontation right of a codefendant? Will it require severance? When should the claim of use immunity be brought to the attention of the trial judge?
5. What notice will be given the prosecutor in the “other” case?
6. Will the use immunity fall to impeachment if the witness testified in the second case in a fashion contrary to his testimony in the first?
7. Does use immunity extend to criminal activity unknown until the testimony and will knowledge of that activity become “fruit of the poisonous tree” ?
8. Is the use immunity purportedly created violative of sec. 905.01, Stats. ?
9. In a multiple count information or indictment, can testimony with respect to one count acquire use immunity for another count?
10. Does the use immunity prohibit the recall of the witness in the same proceeding?
11. Does the use immunity prevent use of the testimony in a retrial of the same offense?
13. Is use immunity prospective or retroactive in its application ?
*335The list is incomplete but it serves to illustrate the wisdom of Sam Johnson’s observation “whatever is formed for long duration arrives slowly to its maturity.”
Although usually inappropriate, an advisory opinion by a court of last resort has the virtue of finality in its advice to the bench and bar.3 Thoughtful and innovative development of the law is not the exclusive province of courts of last resort. Nevertheless, in the second month of this court’s operation, appeals have been filed at a rate of 146 percent of the expected capacity of this court when it was created by the Legislature less than a year ago. Merely addressing the issues presented by a case will exhaust the court’s capacity.4
I cannot concur in the majority’s broad statement that comment on any pretrial silence is error. I agree that the comment in this case was error because it included post-Miranda warning pretrial silence.
Schumm v. Milwaukee County, 258 Wis. 256, 45 N.W.2d 673 (1951); In re Cooper’s Will, 253 Wis. 550, 34 N.W.2d 667 (1948); City of Waukesha v. Schessler, 239 Wis. 82, 300 N.W. 498 (1941).
See Frankfurter, “A Note on Advisory Opinions,” 37 Harv. L. Rev. 1002 (1924).
Cf. State ex rel. Jackson v. Coffey, 18 Wis.2d 529 118 N.W.2d 939 (1963).
Saveland v. Green, 36 Wis. 612 (1875).