¶ 29. (concurring). I join the court in its mandate. I write separately to express my disagreement with the majority opinion's reliance on the plain meaning canon to interpret 1987 Wis. Act 27, § 3047(l)(a).
¶ 30. The majority begins and ends its analysis of § 3047(l)(a) by relying on the plain meaning maxim of statutory interpretation: When statutory language is clear on its face, a court's sole function is to apply the statute according to its plain meaning.
¶ 31. I agree with the majority that the primary source of statutory interpretation is the language of the statute. "The task of resolving the dispute over the *451meaning of [a statute] begins where all such inquiries must begin: with the language of the statute itself." United States v. Ron Pair Enters., Inc., 489 U.S. 235, 241 (1989) (citing Landreth Timber Co. v. Landreth, 471 U.S. 681, 685 (1985)).1
¶ 32. The majority opinion concludes that the language of the statute is clear on its face, using a rule of construction often repeated in prior cases: "A statute is ambiguous when it is capable of being understood in two or more different senses by reasonably well-informed persons" but is not rendered ambiguous "if courts differ as to its meaning." Majority op. at 442.2 This rule of construction, if taken at face value, means that a court need not consider judges and courts as reasonably well-informed persons. If judges and courts were considered reasonably well-informed persons, then under this rule of construction when they differed about a law's meaning, the law would be considered ambiguous.
¶ 33. This rule of construction cannot be taken at face value or treated seriously. The rule is just a means to enable a court to ignore another court's or judge's *452interpretation of a statute and to then set forth its interpretation without explanation. Declaring that a statute has a plain meaning and then stating what the plain meaning is avoids any discussion of how the statute should be interpreted.
¶ 34. For many years I have thought this rule — namely that just because judges differ about the meaning of a statute, the statute is not ambiguous — to be plainly foolish. I conclude that when courts or judges disagree about the interpretation of a law, the law is, by definition, capable of being understood in two or more different senses by reasonably well-informed persons even though one interpretation might on careful analysis seem more suitable to this court.
¶ 35. Section 3047(l)(a) does not explicitly govern bad debt reserve of a savings and loan association, the issue presented in this case. The Tax Appeals Commission, the circuit court and the court of appeals — all impartial, well-informed adjudicative bodies — disagreed over the meaning of § 3047(l)(a) with respect to the bad debt reserve in question. The Tax Appeals Commission and court of appeals interpreted § 3047(l)(a) against Lincoln Savings. The circuit court interpreted § 3047(l)(a) in Lincoln Savings's favor. Both the circuit court and the court of appeals declared § 3047(l)(a) to be plain and unambiguous but disagreed over what the plain meaning of § 3047(l)(a) is.
¶ 36. In my view this case cannot be resolved through reliance on the plain meaning rule alone, as the majority opinion suggests. I would instead decide this case by determining which interpretation of § 3047(l)(a) most clearly achieves the legislative goal of *453changing from Wisconsin's old tax system to a federalized tax regime.3
¶ 37. Prior to 1962 Lincoln Savings was subject to federal but not Wisconsin income tax. Between 1962 and 1987 both Wisconsin and federal tax law permitted savings and loans associations to set aside reserves to cover bad debts and to take deductions for bad debts. Each tax system used different calculations for the deductions, and the Wisconsin tax law was less favorable to taxpayers than the federal tax law in calculating the deductions.
¶ 38. The 1987 Wisconsin federalization act required Wisconsin taxpayers to compute their taxable income based on federal tax law rather than Wisconsin tax law. The state legislature recognized that under federalization some taxpayers might lose deductions while others would escape taxation on income. Thus in 1987 the legislature enacted § 3047(l)(a), a transition rule to provide for adjustments over a five-year period. It is against this backdrop that this court must analyze the parties' interpretations of § 3047(l)(a).
¶ 39. Each party's interpretation focuses on different language of § 3047(l)(a).
*454¶ 40. One interpretation of § 3047(l)(a) is that it applies to any double inclusion or omission of income or deduction arising "because of this act," that is, because of the 1987 federalization act. Under this interpretation § 3047(l)(a) is directed at remedying post-1986 tax distortions caused by the 1987 federalization act. Lincoln Savings urges this interpretation by arguing that an adjustment in its bad debt reserve is required to eliminate post-1986 distortions caused by federalization.
¶ 41. Another interpretation of § 3047(l)(a) is that taxpayers are required to subtract from income any item of income, loss or deduction "in order to avoid the double inclusion, or omission, of any item of income, loss or deduction" (emphasis added). Under this reasoning Lincoln Savings's pre-1962 federal deductions were not omitted for Wisconsin tax purposes because Lincoln Savings was not subject to Wisconsin income tax before 1962. Under this view of § 3047(l)(a) Lincoln Savings cannot recoup the pre-1962 Wisconsin tax deductions.
¶ 42. While both interpretations of § 3047(l)(a) are reasonable, I conclude that Lincoln Savings's interpretation of § 3047(l)(a) is more consistent with the state legislature's ultimate goals of federalization of Wisconsin corporate taxes and ameliorating the impact of changing to the post-1986 system of computing Wisconsin taxable income. I would therefore adopt Lincoln Savings's interpretation of § 3047(l)(a).
¶ 43. For the foregoing reasons I join the court's mandate and write separately.
*455¶ 44. I am authorized to state that Justice William A. Bablitch, Justice Ann Walsh Bradley and Justice N. Patrick Crooks join this opinion.
I also agree with the majority that the purpose of statutory interpretation is to ascertain the intent of the legislature.
The majority opinion also states that "a statute is not rendered ambiguous merely because the parties disagree as to its meaning." Majority op. at 441-442. When parties disagree, I would adopt the approach urged by Professor Hurst: "If on its face the text supports the position of one contestant, due regard to the text suggests that a substantial burden of persuasion should rest on the opponent to prove that the statute had a different meaning." J. Willard Hurst, The Legislative Branch and the Supreme Court, 5 U. Ark. L.J. 487, 789 (1982). See also J. Willard Hurst, Dealing With Statutes 49-50 (1982).
Extrinsic matters such as the statute's context, subject matter, legislative history and the object to be accomplished assist in ascertaining legislative intent. This court has recognized that" '[i]t would be anomalous to close our minds to persuasive evidence of intention [of the legislature] on the ground that reasonable men could not differ as to the meaning of the words. . . .The meaning to be ascribed. . .can only be derived from a considered weighing of every relevant aid to construction.'" State v. Hervey, 113 Wis. 2d 634, 641 n.9, 335 N.W.2d 607 (1983) (quoting United States v. Dickerson, 310 U.S. 554, 562 (1940)).