This is an appeal from the dismissal of a medical malpractice action in which the plaintiffs’ decedent Dale Jensen died as a result of negligence on the part of an emergency room physician and the hospital. The plaintiffs settled with the defendant doctor and went to trial against the hospital. The jury returned a special verdict, finding plaintiffs’ decedent 46 percent negligent in causing his own death; Inter-mountain Health Care, Inc., 36 percent neg*904ligent; and the doctor, 18 percent negligent. Judgment was entered in favor of plaintiff Shirley J. Jensen and against the defendant hospital. The trial court then set aside the original award and entered a judgment of no cause of action. We reverse.
The issue in this case is one of first impression. It is whether the Utah Comparative Negligence Act requires the negligence of each defendant in a multi-defend-ant case to be compared individually against the negligence of the plaintiff or whether the total negligence of all the defendants should be compared to that of the plaintiff to determine whether a particular defendant is liable. Under the latter approach, or the “unit” rule, the negligence of all defendants is taken together in making the comparison; under the “Wisconsin” rule, the negligence of each defendant is compared against the plaintiffs negligence to determine whether a particular defendant is liable.
Thus, under the “unit” rule, the plaintiffs’ decedent’s 46 percent negligence in this case is compared with the combined 54 percent negligence of the defendants, and the plaintiffs would therefore be entitled to recover against the defendant. Under the “Wisconsin” rule, which was applied by the trial court, the negligence attributed to plaintiffs is greater than that of Inter-mountain’s negligence by itself, and plaintiffs would not recover.
Intermountain Health Care argues that the trial court’s ruling is correct on the ground that Utah intended to adopt the “Wisconsin” rule. The first section of the Utah Comparative Negligence Act, U.C.A., 1953, § 78-27-37 constitutes the whole of the one-section Wisconsin Act. Contrary to the Wisconsin statutory scheme, the Utah Act is a comprehensive, seven-section statutory scheme that deals with joint and several liability of multiple tortfeasors and the use of special verdicts for determining relative degrees of fault. The Utah Act must therefore be construed in light of, and to harmonize with, those additional sections.
I.
When construed as a whole, the Utah Comparative Negligence Act indicates that the legislative intent was not to adopt the Wisconsin rule of comparative liability. Unless the whole Utah Act is considered together, the result would be to misconstrue not only Section 1, but also other sections of the Act. Thus, adoption of the Wisconsin rule would nullify in part critical parts of the Utah Act and would produce results unfair to both plaintiffs and defendants.
Even the Wisconsin Supreme Court has become disenchanted with the fairness of its own rule. It has stated: “The majority of the court has become convinced that comparing the negligence of the individual plaintiff to that of the individual tort-feasor — rather than comparing the negligence of the individual plaintiff to that of the combined negligence of the several tortfeasors who have collectively contributed to plaintiff’s injuries — leads to harsh and unfair results_” May v. Skelley Oil Co., 83 Wis.2d 30, 264 N.W.2d 574, 578 (1978). And the Arkansas Supreme Court, in rejecting the Wisconsin rule, has characterized that rule as being “demonstrably unjust.” Walton v. Tull, 234 Ark. 882, 892-93, 356 S.W.2d 20, 26 (1962).
We recognize that when the Legislature adopts a statute from another state, the presumption is that the Legislature is familiar with that state’s judicial interpretations of that statute and intends to adopt them also. 73 Am.Jur.2d Statutes § 333 at 46 (1974). However, that canon of statutory construction is not a hard and fast principle; it is subject to a number of exceptions, several of which are directly applicable in the instant case. In the first place, it is not applicable where there have been material changes made in the second statute. Copper Queen Consolidated Mining Co. v. Territorial Board of Equalization, 206 U.S. 474, 27 S.Ct. 695, 51 L.Ed. 1143 (1907); Stutsman County v. Wallace, 142 U.S. 293, 12 S.Ct. 227, 35 L.Ed. 1018 (1892); White v. White, 196 Ark. 29, 116 S.W.2d 616 (1938); McNary v. State, 128 *905Ohio St. 497, 191 N.E. 733 (1934). See also 73 Am.Jur.2d Statutes § 334 at 477 (1974). Secondly, the above-stated rule of statutory construction is subject to the exception that if the borrowed statute is “given a different setting in the adopting state” the construction placed upon the statute in the originating state need not be followed. Id. at 478; State v. Reed, 39 N.M. 44, 39 P.2d 1005 (1934); 102 A.L.R. 995 (1936).
Furthermore, the canon of construction referred to is not applicable where the courts of the adopting state are clearly of the opinion that the foreign construction is erroneous. Whitney v. Fox, 166 U.S. 637, 17 S.Ct. 713, 41 L.Ed. 1145 (1897); 73 Am.Jur.2d, supra, at 478. In addition, “the interpretation of an adopted statute by decisions of dates subsequent to that of the adoption cannot have been adopted by the statute. The adoption is accordingly not presumed to carry such construction, which is not binding upon the courts of the adopting state.” 73 Am. Jur.2d Statutes § 335 at 478 (1974), and cases cited.1
In any event, this Court has indicated a healthy and deserved skepticism about giving too much credence to the various canons of statutory construction. In Salt Lake City v. Salt Lake County, Utah, 568 P.2d 738 (1977), the Court stated that rules of construction may be useful when applied in appropriate instances, “[b]ut helpful as rules of construction often are, they are useful guides but poor masters; and they should not be regarded as having any such rigidity as to have the force of law, or distort an otherwise natural meaning or intent. Their only legitimate function is to assist in ascertaining the true intent and purpose of the statute.” Id. at 741.
II.
The Utah Comparative Negligence Act, U.C.A., 1953, § 78-27-37, et seq., was passed in 1973. 1973 Utah Laws, ch. 209. Chapter 209 adds six additional sections to the Wisconsin provision. The Utah Act provides in full text:
UTAH COMPARATIVE NEGLIGENCE ACT
Section 1. Actions based on negligence or gross negligence — Contributory negligence.
Contributory negligence shall not bar recovery in an action by any person or his legal representative to recover damages for negligence or gross negligence resulting in death or in injury to person or property if such negligence was not as great as the negligence or gross negligence of the person against whom recovery is sought, but any damages allowed shall be diminished in the proportion to the amount of negligence attributable to the person recovering. As used in this act, “contributory negligence” includes “assumption of the risk.”
Section 2. Powers of the court.
The court may, and when requested by any party shall, direct the jury to find separate special verdicts determining (1) the total amount of damages suffered and (2) the percentage of negligence attributable to each party; and the court shall then reduce the amount of the damages in proportion to the amount of negligence attributable to the person seeking recovery.
Section 3. Right of contribution among joint tortfeasors.
(1) The right of contribution shall exist among joint tortfeasors, but a joint tort-feasor shall not be entitled to a money judgment for contribution until he has, by payment, discharged the common liability or more than his pro rata share thereof.
Section 4. Contribution among joint tortfeasors.
(1) A joint tortfeasor who enters into a settlement with the injured person shall not be entitled to recover contribution from another joint tortfeasor whose lia*906bility to the injured person is not extinguished by that settlement.
(2) When there is a disproportion of fault among joint tortfeasors to an extent that it would render inequitable an equal distribution by contribution among them of their common liability, the relative degrees of fault of the joint tort-feasors shall be considered in determining their pro rata shares, solely for the ;purpose of determining their rights of contribution among themselves, each remaining severally liable to the injured person for the whole injury as at common law.
(3) As used in this section, “joint tort-feasor” means one of two or more persons, jointly or severally liable in tort for the same injury to person or property, whether or not judgment has been recovered against all or some of them.
Section 5. Exemptions.
Nothing in this act shall affect:
(1) The common law liability of the several joint tortfeasors to have judgment recovered, and payment made, from them individually by the injured person for the whole injury. However, the recovery of a judgment by the injured person against one joint tortfeasor does not discharge the other joint tort-feasors.
(2) Any right of indemnity which may exist under present law.
(3) Any right to contribution or indemnity arising from contract or agreement. Section 6. Release of one or more joint tortfeasors.
A release by the injured person of one joint tortfeasor, whether before or after judgment, does not discharge the other tortfeasors, unless the release so provides, but reduces the claim against the other tortfeasors by the greater of: (1) The amount of the consideration paid for that release; or (2) the amount or proportion by which the release provides that the total claim shall be reduced.
Section 7. Effect of releases on other joint tortfeasors.
(1) A release by the injured person of one joint tortfeasor does not relieve him from liability to make contribution to another joint tortfeasor unless that release:
(a) Is given before the right of the other tortfeasor to secure a money judgment for contribution has accrued; and
(b) Provides for a reduction, to the extent of the pro rata share of the released tortfeasor, of the injured person’s damages recoverable against all the other tortfeasors.
(2) This section shall apply only if the issue of proportionate fault is litigated between joint tortfeasors in the same action.
(Emphasis added.)
Section 1 of the Utah Act is comparable to and comprises the whole of the Wisconsin Comparative Negligence Act. At the time of the adoption of the Utah Act, the Wisconsin comparative negligence provision contained no other provisions, let alone provisions comparable to Sections 2 through 7 of the Utah Act.2
The best evidence of the true intent and purpose of the Legislature in enacting the Act is the plain language of the Act. The meaning of a part of an act should harmonize with the purpose of the whole act. Separate parts of an act should not be construed in isolation from the rest of the act. Osuala v. Aetna Life & Casualty Co., Utah, 608 P.2d 242 (1980); Monson v. Hall, Utah, 584 P.2d 833 (1978). Thus, the meaning of the Comparative Negligence Act cannot properly be determined without taking into account Sections *9071 through 7 of the Act and the purposes they were designed to effectuate. Indeed, as appears below, Sections 2, 3, 4, and 5 are particularly relevant and require harmonizing with each other and the other sections of the Act. See generally Park and Recreation Commission v. Department of Finance, 15 Utah 2d 110, 388 P.2d 233 (1964). The Legislature can hardly have intended that a construction should be placed on Section 1 that would result in harsh and unfair results in applying the remainder of the Act.
It is obvious from the language of the Act that the intent of the Legislature was to accomplish two objectives: first, to alleviate the harshness of the old common law doctrine of contributory negligence; and second, to provide for a system of loss allocation by apportioning liability based at least in part on fault and to provide for contribution among tortfeasors according to fault.
It is also clear from Section 4(2) of the Act that joint tortfeasors are liable for contribution without regard to their degree of negligence unless there is such a “disproportion of fault” that it would be “inequitable” for there to be “an equal distribution by contribution among them of their common liability....” If the trial court makes a finding that contribution by equal distribution among the joint tortfeasors (all of them) would be inequitable, then the “relative degrees of fault of the joint tort-feasors shall be considered in determining their pro rata shares ...,” but that is “solely for the purpose of determining their rights of contribution among themselves, each remaining severally liable to the injured person for the whole injury as at common law." Section 4(2) (emphasis added).
That language is as clear as language permits. A construction of Section 1 of the Act requiring application of the Wisconsin rule would clearly conflict with the language of Section 4(2). The determination of the “relative degrees of fault of joint tortfeasors” may not be used to excuse some tortfeasors from liability. That determination is “solely” to effectuate an equitable contribution among the tortfeasors. Section 4(3) reinforces the stated purpose of Section 4(2). Section 4(3) states that the term “joint tortfeasor” means “one of two or more persons, jointly or severally liable in tort for the same injury to person or property..-.” even though judgment has been recovered against all or only some of such persons. Thus, the rule established by Section 4(2) makes all defendants subject to joint and several liability for the whole injury, and that rule is subject only to the rule governing contribution. It is irrelevant whether a tortfeasor’s negligence in a multi-defendant case is greater or lesser than the plaintiffs, irrespective of whether the tortfeasor is a party defendant. Section 5 reinforces the same concept.
Section 1 of the Act must also be read in light of Section 2. The latter section provides that the court may, on its own initiative or when requested by a party, direct the jury to find separate special verdicts in determining the total amount of damages suffered and the percentage of negligence attributable to , each party. As under Section 4, the determination of the degrees of fault is not to be used to excuse any tortfeasor from liability in a multi-de-fendant case; it is rather to be used only for the purpose of dealing with the issue of damages. Thus, the total amount of damages is to be reduced solely by the amount of damages attributable to the “person seeking recovery” — not by any other factor — as the Wisconsin rule would require in some cases.
Thus, the Wisconsin rule directly conflicts with the explicit statutory language in both Sections 1 and 2, which only allow reduction of the total “amount of damages” by the amount of damages attributable “to the person seeking recovery,” and not by the amount of damages attributable to a defendant whose negligence is found to be less than the negligence of the plaintiff. This double reduction would also violate the express statutory mandate that the “relative degrees of fault of the joint tort-feasors shall be considered in determining the pro rata shares, solely for the purpose *908of determining their rights of contribution among themselves _” Section 4(2).
Obviously, the ascertainment of the relative degrees of fault of joint tortfeasors is not necessary for determining whether the plaintiff can recover against a defendant or defendants at all. Whether the plaintiff can recover is a threshold issue that the trier of fact decides by determining whether the plaintiffs negligence, if any, exceeds the totality of the tortfeasors’ negligence. No special verdict is required for that determination. That is precisely why Section 2 of the Act does not make it mandatory that there be special verdicts returned in all cases. In addition, both Sections 1 and 2 of the Act make clear beyond peradventure that the only allowable deduction from the total damage suffered is the amount attributable to the plaintiff’s proportion of negligence. There is no authorization for deducting any other amount from the total damage figure.
If a tortfeasor were not liable as a result of the “Wisconsin” or “individual” rule of comparison, a serious inequity in the distribution of financial liability among tort-feasors would arise. Under Section 5, nothing in the Utah Act affects the “common law liability of the several joint tort-feasors to have judgment recovered, and payment made, from them individually by the injured person for the whole injury ” (emphasis added). One inequitable consequence of applying the Wisconsin rule to the Utah Act would be to make a defendant liable for that portion of the injury for which he was not responsible and for which another tortfeasor was. That result is counter to the concepts of comparative negligence and joint and several liability.
Furthermore, it should be noted that the language of Section 1, as such, is not necessarily inconsistent with the unit rule. That section only refers to a plaintiff’s negligence not being “as great as the negligence or gross negligence of the 'person against whom recovery is sought .... ” (Emphasis added.) The statutory language is not the “negligence of any person against whom recovery is sought”; rather the language used was intended to mean “the person or persons” so as to include both single-defendant and multi-defendant cases. That construction is suggested by the text and is in full harmony with U.C.A., 1953, § 68-3-12, which provides rules for construction of Utah statutes. Subparagraph (6) states, “The singular number includes the plural, and the plural the singular.” Application of § 68-3-12 makes Section 1 of the Utah Comparative Negligence Act harmonious with the rest of the Act. Graci v. Damon, 6 Mass.App. 160, 374 N.E.2d 311, 317 (1978), applied a comparable Massachusetts statutory provision to the precise word at issue here, thereby requiring that the statute be read to mean “persons” in a multi-defendant case so that the plaintiff’s negligence was compared against the aggregate of all the defendants.
The meaning that emerges from Section 1 by applying § 68-3-12(6) is consistent with the rulings of a number of courts which have held that the singular term defendant (or other synonymous nouns) also means the plural. Walton v. Tull, 234 Ark. 882, 356 S.W.2d 20 (1962); Grad v. Damon, 6 Mass.App. 160, 374 N.E.2d 311 (1978), aff'd, 376 Mass. 931, 383 N.E.2d 842 (1978); Bradley v. Appalachian Power Co., W.Va., 256 S.E.2d 879 (1979). See contra Odenwalt v. Zaring, 102 Idaho 1, 624 P.2d 383 (1981); Board of County Commissioners v. Ridenour, Wyo., 623 P.2d 1174 (1981).
III.
The Wisconsin rule is the minority position in this country. Only five states adhere to it, whereas at least fourteen jurisdictions have adopted the unit rule of comparison either by statute or case law. Heft and Heft, Comparative Negligence Manual, Appendix II (Supp.1983). Another four states have adopted the doctrine of pure comparative negligence by judicial decision—Alaska, Kaatz v. State, 540 P.2d 1037 (1975); California, Li v. Yellow Cab Co., 13 Cal.3d 804, 119 Cal.Rptr. 858, 532 P.2d 1226 (1975); Florida, Hoff*909man v. Jones, 280 So.2d 431 (1973); and Michigan, Kirby v. Larson, 400 Mich. 585, 256 N.W.2d 400 (1977). In addition, four other states — Mississippi, New York, Rhode Island, and Washington — have adopted unit comparative negligence by statute. See Bradley v. Appalachian Power Co., supra, 256 S.E.2d at 883. At least twenty-seven states have statutes ameliorating the effect of the harsh common law doctrine of contributory negligence. Fundamentally, these statutes permit a negligent plaintiff to recover as long as his negligence is not in excess of some amount, usually 50 percent. Id. at 882, n. 4.
The refusal of the majority of the states that have dealt with the subject to adopt the Wisconsin rule indicates a widespread perception that that rule is not sound. Almost without variation, those states that have adopted the Wisconsin rule have done so on the rather wooden analysis that the Legislature must have intended to adopt the court decisions construing the Wisconsin statute as a part of that state’s law.
Even apart from the evident meaning and effect of the sections which were added to the first section of the Act to provide a comprehensive treatment of the subject matter, we would be reluctant to construe the Act to enact a policy that is so inequitable that even the Wisconsin Supreme Court, based on much experience with that policy, has severely criticized it.
IV.
The defects of the Wisconsin rule suggest why the Legislature undertook to change the Wisconsin rule. First, it is axiomatic that there can be no more than 100 percent negligence when the negligence of all defendants and the plaintiff is added up. But that would never be the case in multi-defendant cases in which a defendant is excused from liability under the Wisconsin rule. Thus, for example, if a plaintiff is 20 percent negligent in stopping on a highway and each of four defendants who rear-end the plaintiff is 20 percent negligent, the plaintiff under the Wisconsin rule will recover nothing because the plaintiffs 20 percent negligence is not applied against the total negligence of the defendants. Thus, under the Wisconsin rule, plaintiffs negligence is used four different times to cancel out each of the defendants’ negligence. By the magic of the formula employed, the plaintiffs 20 percent becomes an effective 80 percent, and the total percentage of negligence in the case, combining that attributable to the plaintiff and that attributable to the defendants, totals 160 percent. If plaintiff’s negligence were applied once, there would be a total of 100 percent negligence when plaintiff’s and defendants’ negligence are combined.
The unfairness of the Wisconsin rule is also apparent in a situation where a plaintiff is 33⅛ percent negligent and each of two defendants is also 33⅛ percent. Under those circumstances, the plaintiff could recover nothing. However, if the same injury were inflicted by the same cause but only one defendant were responsible for producing the injury, the plaintiff would recover 66% percent of the damages inflicted.
In short, one of the anomalous consequences of the Wisconsin rule is that the more defendants who inflict an injury, the less likely a plaintiff will be to recover. Thus, if 50 riparian landowners are responsible for polluting a stream and are negligent in equal percentages for causing 98 percent of the damage to the property of a downstream owner who is only 2 percent contributorily responsible, the plaintiff recovers nothing! The Utah Act was not intended to adopt a rule that would permit such extraordinary consequences.3
*910It may be that Wisconsin has reason to live with such a rule, but Utah does not, and the Legislature in effect has said so.
Reversed and remanded for entry of judgment on the verdict. Costs to appellants.
HOWE and DURHAM, JJ., concur. OAKS, J., having disqualified himself, does not participate herein; DEE, District Judge, sat. •. Such would be the case if the Utah Act were borrowed from Idaho, as is possible.
. The entire text of the Wisconsin Comparative Negligence Statute enacted in 1971 provides as follows:
Contributory negligence shall not bar in an action by any person or his legal representative to recover damages for negligence resulting in death or an injury to person or property, if such negligence was not greater than the negligence of the person against whom recovery is sought, but any damages allowed shall be diminished in the proportion to the amount of negligence attributable to the person recovering.
Wis.Stat. § 895.045 (1975).
. There are three situations sometimes asserted to demonstrate that the unit rule leads to unfair results. The first is the situation presented by the instant case; the plaintiff's negligence is less than the cumulative negligence of all the tort-feasors but is more than a particular defend*910ant's. That is said to be unfair because a plaintiff should not be able to recover from a defendant who is less negligent than the plaintiff. See Bd. of County Comm'rs v. Ridenour, Wyo., 623 P.2d 1174 (1981). The second situation is where there are two defendants and one plaintiff; all parties are 33 ¼ percent at fault. Under the unit rule, the plaintiff recovers 66⅜ percent of his or her total damages. That is said to be unfair because if there were only one defendant who is 50 percent liable, the plaintiff would recover nothing.
However, the plaintiff is not the primary cause of the injuries in either of the two situations discussed and therefore should be entitled to recover. The defendants, meanwhile, are required to do nothing more than compensate the plaintiff for the injury in proportion to their fault, with the plaintiff absorbing his own proportion of fault.
The third alleged inequitable result under the unit rule arises when one defendant is judgment proof. For example, suppose plaintiff is 15 percent negligent, defendant A is 10 percent negligent, and defendant B is 75 percent negligent; B, however, is judgment proof. Under the Utah statute, A might be liable for 85 percent of plaintiff's damages. That situation, however, is a product of the rule of joint and several liability — not comparative fault. Prior to adoption of the comparative negligence statute, a plaintiff free from contributory negligence could recover the entire amount of damages from a defendant whose negligence was slight. And the problem of the judgment-proof defendant exists under the Wisconsin rule as well. Suppose plaintiff is 10 percent at fault, defendant A is 15 percent at fault, and defendant B is 75 percent at fault; B is judgment proof. Under the Wisconsin rule, defendant A is liable for 90 percent of plaintiff's damages, a result no less inequitable than that reached by the unit rule.