We granted certiorari to review the court of appeals’ decision in Guzman v. Gleason, Colo.App., 598 P.2d 145 (1979), which addressed the issue of mistake in connection with the execution of a guardian’s release for his daughter’s personal injury claim. The trial court had granted the defendants’ motion for summary judgment on the ground that any mistake in the execution of the release was a unilateral mistake in the prognosis for recovery rather than a mistake about the nature of the injury. The court of appeals reversed and remanded, holding that there was a genuine issue of *380fact as to the nature of the mistake and summary judgment was inappropriate. We affirm the court of appeals.
On September 29, 1970, Darlene Benavi-dez, then a fourteen-year-old minor, was struck on the head by a vending machine that fell from a truck operated by Irwin Gleason in the course of his employment with Coin Fresh, Inc. (defendants). Darlene Benavidez has since married and is now known as Darlene Guzman (plaintiff). Immediately after the accident she was taken to Denver General Hospital for examination. She complained of headache, vomiting and some disorientation and, after two days of observation and testing, her injury was diagnosed as a left temporal lobe contusion and she was released as improved. On October 13,1970, the plaintiff was readmitted to the hospital with complaints similar to those previously experienced. Further testing resulted in a diagnosis of left intratemporal lobe hematoma and the plaintiff was discharged as improved on October 20, 1970. Shortly thereafter plaintiff returned to high school and a normal routine. She and her parents, Mr. and Mrs. Benavi-dez, believed that plaintiff had fully recovered from the injury.
In November 1970 the plaintiffs parents retained an attorney in connection with their daughter’s claim. Approximately two years later this attorney initiated settlement negotiations with the defendants’ insurance carrier. It was mutually agreed that the case be settled for $6,114.35. The insurance carrier hired an attorney to prepare a petition for the probate court’s approval of the settlement and the appointment of the plaintiff’s father, Mr. Benavi-dez, as guardian of his minor daughter’s estate. The probate court approved the settlement and Mr. Benavidez, as duly appointed guardian, executed a general release of his daughter’s claim against the defendants.
In May 1974, approximately forty-four months after the accident, the plaintiff experienced her first epileptic seizure during her senior year in high school. Other seizures followed. Having become emancipated through marriage, she retained her present attorneys and a complaint was filed in November 1975. The complaint sought money damages against the defendants for negligently causing personal injuries to the plaintiff in the accident of September 29, 1970. The defendants in their answer raised as an affirmative defense the release executed by the guardian and endorsed on their answer a demand for a jury trial. Thereafter, the defendants filed a motion for summary judgment on the basis of the guardian’s release. The plaintiff countered with a motion to set aside the release on the ground that it was executed under a mistake as to the nature of the injury actually sustained. The court heard both motions in a consolidated hearing on November 14, 1977.
At the commencement of the motions-hearing the attorneys advised the court that the two pending motions involved the identical issue: the validity of the release. The plaintiff’s attorney then offered to proceed to a court trial on this issue and to accept the court’s decision as the final judgment in the matter. However, the defendants’ attorney rejected the offer and stated to the court that he expected the court to rule on the issue within the format of a summary judgment proceeding. At this point the court stated: “This is a summary judgment — I mean, I am just going to rule on the things before me.”1
*381During the motions-hearing the plaintiff presented a neurologist who testified that the first diagnosis of post-traumatic epilepsy was made after the first seizure in 1974. He also stated that a monitored program of intermittent electroencephalographic testing between the accident and the seizure would not have necessarily disclosed the epileptic condition. The affidavits and testimony of the plaintiff and her parents established that they were never informed of actual or potential epilepsy with respect to the injury suffered and that the release would not have been executed if they were aware of any risk of that condition developing.
During legal argument at the motions-hearing the defense attorney made reference to pleadings, affidavits, deposition testimony and pertinent legal authority for the purpose of establishing the factual and legal predicates for summary judgment under C.R.C.P. 56(c). Approximately three weeks after the hearing the court entered a written order granting the defendants’ motion for summary judgment and denying the plaintiff’s motion to set aside the release for the following reasons:
“The Court finds that the facts of this case are governed by Davis v. Flatiron Materials Co., 182 Colo. 65, 511 P.2d 28 (1973). Any mistake existing at the time the release was executed was not a mutual mistake of fact, but rather a unilateral mistake of prognosis by the plaintiff.... At the time the release was executed, the plaintiff should have known that traumatic epilepsy could result from her injury.”
The court of appeals reached an opposite conclusion, finding this case indistinguishable from Scotton v. Landers, 190 Colo. 27, 543 P.2d 64 (1975), and holding that “there was evidence upon which the trier of fact could well conclude that the settlement was based on a basic mistake.”
The defendants raise alternate arguments for reversal of the court of appeals. First, they argue that the plaintiff was not entitled to a jury trial on the issue of mistake in the execution of the release and, therefore, the trial court’s denial of the plaintiff’s motion to set aside the release constituted an adjudication on the merits. Alternatively, they claim that the trial court properly granted summary judgment because any mistake was a unilateral mistake in prognosis as to the plaintiff’s future course of recovery from a known injury and not a mistake as to the nature of the injury itself.
I. The Effect of the Motions-Hearing on the Right to a Jury Trial
The defendants assert that the court’s denial of the plaintiff’s motion to set aside the release constituted an adjudication on the merits. Their argument stems from two inferences which they believe find support in the record: (1) the filing of the motion to set aside the release invoked the equity jurisdiction of the court and transformed the character of the action from a legal to an equitable one for which a jury trial was inappropriate; and (2) the plaintiff’s presentation of evidence in support of the motion effected a waiver of a jury trial on all issues relating to the release. Our *382interpretation of the record is different from that urged by the defendants.
The record clearly demonstrates that the district judge considered both motions — the defendants’ motion for summary judgment and the plaintiff’s motion to set aside the release — under the rubric of summary judgment proceedings. When he heard and ruled on the motions he was not acting as a chancellor in equity or as the ultimate trier of fact, but as a judge determining that “there is no genuine issue as to any material fact and the moving party is entitled to judgment as a matter of law.” C.R.C.P. 56(c).
Contrary to the defendants’ argument, the plaintiff’s filing of the motion to set aside the release did not transform the character of the proceedings from a legal to an equitable one. Although there is no constitutional right to a jury trial in civil cases in Colorado, Colo.Const. Art. II, Sec. 23; Johnson v. Neel, 123 Colo. 377, 229 P.2d 939 (1951); Parker v. Plympton, 85 Colo. 87, 273 P. 1030 (1928), C.R.C.P. 38(a) provides that an issue of fact must be tried to a jury upon demand in an action for personal injuries. Here, the complaint sounds in negligence and seeks relief in the form of money damages. Historically, actions to recover money damages for personal injuries are legal, not equitable, and upon proper demand should be tried to a jury rather than the court. 5 J. Moore, Federal Practice § 38.11[5] and § 38.19[1] (2d ed. 1980). In Colorado “whether an issue of fact must be tried to a jury ... depends upon the character of the action in which the issue is joined.” Setchell v. Dellacroce, 169 Colo. 212, 215, 454 P.2d 804, 806 (1969); see Miller v. District Court, 154 Colo. 125, 388 P.2d 763 (1964); Esselstyn v. United States Gold Corp., 59 Colo. 294, 149 P. 93 (1915); Jacobs v. Prudential Ins. Co., 35 Colo.App. 423, 533 P.2d 516 (1975); Miller v. Carnation Co., 33 Colo.App. 62, 516 P.2d 661 (1973).
The plaintiff’s motion to set aside the release no more impacted on the basic character of the action than did the defendants’ assertion of the affirmative defense of release in their answer. In fact, the defendants acknowledged implicitly the legal character of this action by endorsing on that answer a demand for a jury trial pursuant to C.R.C.P. 38(b). Notwithstanding the issue relating to the validity of the release, the action remains essentially a tort action for money damages triable to a jury. See, e. g., Callen v. Pennsylvania Railroad Co., 332 U.S. 625, 68 S.Ct. 296, 92 L.Ed. 242 (1948); McCarthy v. Eddings, 109 Colo. 526, 127 P.2d 883 (1942); Oman v. Mishler, 92 Colo. 476, 22 P.2d 132 (1933); Yelloway, Inc. v. Garretson, 89 Colo. 375, 3 P.2d 292 (1931).
The defendants’ argument that the plaintiff waived a jury trial by presenting evidence at the motions-hearing is similarly unpersuasive. The plaintiff’s motion to set aside the release was filed in contravention of the defendants’ motion for summary judgment. In view of the court’s statement at the commencement of the motions-hearing that “this is a summary judgment” proceeding, the plaintiff’s proffered testimony at that hearing apparently was directed to the establishment of sufficient factual issues so as to render a summary judgment for the defendants inappropriate.
Moreover, a demand for a trial by jury by one party may not be withdrawn without the consent of all parties. C.R.C.P. 38(d); Forster v. Superior Court, 175 Colo. 444, 488 P.2d 202 (1971); see also Young v. Colorado National Bank, 148 Colo. 104, 365 P.2d 701 (1961); Jaynes v. Marrow, 144 Colo. 138, 355 P.2d 529 (1960). Here, the plaintiff offered to waive a jury trial on the issues relating to the release but the defendants precluded that offer from ripening into a waiver. Since the defendants refused to waive a jury trial, the motions-hearing was not converted into a trial on the merits.2 Thus, the court’s determination of the defendants’ motion for summary judgment must be evaluated under the standards appropriate for that proceeding.
*383II. The Propriety of Summary Judgment
The defendants urge two reasons why the court of appeals erred in reversing the trial court’s entry of summary judgment. First, they argue that the mistake related to a future complication of a known injury, as distinct from a mistake about the nature of the injury actually suffered in the accident. Next, they contend that the release was a general release encompassing both known and unknown injuries and it thereby precluded rescission even for a mistake as to an unknown injury.
Since these arguments are presented to us in the context of a summary judgment review, the determinative considerations are whether the record shows a genuine issue as to any material fact and whether the defendants are entitled to judgment as a matter of law. C.R.C.P. 56(c). Summary judgment is a drastic remedy and should be granted only where the evidential and legal prerequisites are clearly established. E. g., McKinley Construction Co. v. Dozier, 175 Colo. 397, 487 P.2d 1335 (1971); Primock v. Hamilton, 168 Colo. 524, 452 P.2d 375 (1969); Flanders v. Kochenberger, 118 Colo. 104, 193 P.2d 281 (1944); Hatfield v. Barnes, 115 Colo. 30, 168 P.2d 552 (1946). Having due regard for these stringent standards of review and after careful consideration of the record before us, we reject defendants’ contentions.
A. Mistake as a Basis For Avoidance of Release
Cases addressing the problem of mistake in the settlement of personal injury claims reflect a tension stemming, on the one hand, from the general need for finality in the contractual settlements of actual or potential lawsuits and, on the other hand, from a recognized need to alleviate the distorting and unintended effects which human error can impose on a transaction. See, e. g., II G. Palmer, The Law of Restitution § 11.2, 12.22 (1978); Dobbs, Conclusiveness of Personal Injury Settlements: Basic Problems, 41 N.C.L.Rev. 665 (1963); Note, Avoidance of Tort Releases, 13 W.Res.L. Rev. 768 (1962); Havighurst, Problems Concerning Settlement Agreements, 53 Nw.U, L.Rev. 283 (1958). Although the approaches are not totally discrete, they do lean in different directions. One approach denies rescission even though the injuries were not known or suspected at the time of the settlement. E. g., Tewksbury v. Fellsway Laundry, 319 Mass. 386, 65 N.E.2d 918 (1946). Under this view the releasor assumes the risk that the nature and extent of known injuries might be more severe than was believed at settlement. Another approach allows rescission based on any mistake as to the condition of the injured claimant, whether the mistake relates to the nature of the injuries or to their further consequences. E. g., Graham v. Atchison, T. & S. F. Ry. Co., 176 F.2d 819 (9th Cir. 1949); Robert Hind, Ltd. v. Silva, 75 F.2d 74 (9th Cir. 1935); Reed v. Harvey, 253 Iowa 10, 110 N.W.2d 442 (1961). Midway between these approaches is the view that rescission is available for mistakes relating to the nature of known injuries but not for mistakes as to the future course and effects of those injuries. E. g, Casey v. Proctor, 59 Cal.2d 97, 378 P.2d 579, 28 Cal.Rptr. 307 (1963); Hall v. Strom Constr. Co., 368 Mich. 253, 118 N.W.2d 281 (1962); Farrington v. Harlem Sav. Bank, 280 N.Y. 1, 19 N.E.2d 657 (1939); Doyle v. Teasdale, 263 Wis. 238, 57 N.W.2d 381 (1953). The assumption here is that rescission must be based on mistake, and mistake for legal purposes must relate to a past or present fact rather than an opinion or prophecy about the future. See II G. Palmer, supra at § 12.22.
This latter approach represents the rule in this jurisdiction. It was presaged in McCarthy v. Eddings, supra. There the plaintiff suffered a broken arm but, based on his doctor’s representation, believed that the injury was temporary in duration and executed a release. Thereafter, he discovered that the broken bones in the arm had not united and the resulting disability was permanent. We affirmed the jury verdict for the plaintiff and held that a release obtained as the result of a mutual basic mistake could be set aside as ineffective.
The McCarthy rule was further refined in Davis v. Flatiron Materials Co., 182 Colo. *38465, 511 P.2d 28 (1973), which upheld the validity of a release in the context of a known aggravation of pre-existing cervical osteoarthritis from an automobile accident. After executing a release Mrs. Davis experienced a worsening of symptoms, was involved in another accident, and subsequently underwent spinal surgery. Noting that the injury was correctly diagnosed and that the plaintiff was fully informed about the nature of her condition, we held that to justify rescission the mistake “must relate to a present existing fact or a past fact,” Id. at 71, 511 P.2d at 31, rather than as there present, a mistake concerning the future course of recovery from the known injury.
We again addressed this problem in Scotton v. Landers, 190 Colo. 27, 543 P.2d 64 (1975), where the plaintiff, believing that he suffered a fractured rib and bruises in an automobile accident, executed a general release only to discover shortly thereafter that his spleen had been ruptured and had to be surgically removed. We concluded that the mistake was sufficient to avoid the release because it was grounded in the nature of injuries suffered in the accident.
As McCarthy, Davis and Scotton demonstrate, the distinction between unknown injuries and unknown consequences of known injuries is a useful analytic standard but it does not yield a litmus-type resolution to these problems. The words we use, “though they have a central core of meaning that is relatively fixed, are of doubtful application to a considerable number of marginal cases.” Williams, Language and The Law, 61 L.Q.Rev. 179, 191 (1945), quoted in Ricketts v. Pennsylvania R. Co., 153 F.2d 757, 765, n. 28 (2d Cir. 1946) (Frank, J., concurring). Indeed, this is such a marginal case. With respect to post-traumatic epilepsy, the margin of difference between a mistake in diagnosis and a mistake in prognosis, or the difference between that condition as an injury and as a consequence, cannot easily be fitted into predetermined categories of exclusivity.3
Judge Learned Hand pointed up the difficulty of conceptual differentiation in these matters:
“There is indeed no absolute line to be drawn between mistakes as to future, and as to present facts. To tell a layman who has been injured that he will be about again in a short time is to do more than prophesy about his recovery. No doubt it is a forecast, but it is ordinarily more than forecast; it is an assurance as to his present condition, and so understood.” Scheer v. Rockne Motors Corp., 68 F.2d 942, 945 (2d Cir. 1934).
A similar view was cogently voiced in Clancy v. Pacenti, 15 Ill.App.2d 171, 145 N.E.2d 802 (1957):
“In such cases it is not an article of commerce that is involved, but the human mind and body, still the most complicated and mysterious of all the things that are upon or inhabit the earth. Here, mistakes are easily made and the consequences are more serious than in any other of the affairs of men. A slight abrasion may mean nothing or it may lead to a malignancy. Insignificant pain may mean the beginning of a fatal coronary attack or only a slight intestinal disturbance. Yet, a man cannot and does not live in dread of these possibilities. He accepts assurances that all will be well, even though ultimate consequences cannot be appraised as in matters involving property or services.” Id. at 176-77, 145 N.E.2d at 805.
*385Mistake, by its very nature, involves an erroneous state of mind about an external fact. II G. Palmer, supra, § 11.4. It may stem from a tacit presupposition of an untrue fact or from ignorance of an existing fact. Id. An inquiry into its existence is essentially factual in character. In Scotton v. Landers, supra, we noted that in cases raising the issue of mistake in the execution of a release for a personal injury claim the prime and determinative consideration is whether “the injured party released his claim under a mistaken or false impression that he was fully informed as to the nature of his injuries.” 190 Colo. at 29-30, 543 P.2d at 66.
Knowledge of the nature of an injury requires an awareness and some appreciation of its extent, severity and likely duration. See, e. g., Scheer v. Rockne Motors Corp., supra; McCarthy v. Eddings, supra; Backus v. Sessions, 17 Cal.2d 380, 110 P.2d 51 (1941); Clancy v. Pacenti, supra; Jordan v. Brady Transfer & Storage Co., 226 Iowa 137, 284 N.W. 73 (1939); Mitzel v. Schatz, 175 N.W.2d 659 (N.D.1970); Poti v. New England Road Machinery Co., 83 N.H. 232, 140 A. 587 (1928). Admittedly, line-drawing here is difficult and its direction .may well vary with the thrust of evidence. These basic components of knowledge, however, relate primarily to a comprehension of the basic character of the injury as distinct from a prediction or opinion about the future course of recovery when its basic nature is otherwise known.
Thus the determinative issue here is whether, viewing the evidence in the light most favorable to the plaintiff and drawing all reasonable inferences therefrom in her favor, e. g., Adickes v. S. H. Kress & Co., 398 U.S. 144, 90 S.Ct. 1598, 26 L.Ed.2d 142 (1970); United States v. Diebold, Inc., 369 U.S. 654, 82 S.Ct. 993, 8 L.Ed.2d 176 (1962); Clancy v. Pacenti, supra; 6 J. Moore, Federal Practice § 56.15[1.-00] and § 56.15[3] (2d ed. 1980), there is a genuine factual issue that the guardian was mistaken about the nature of his daughter’s injury when he executed the release.4 In determining this question we focus on what the guardian, as a layman, knew about the injury, and not what the opinion of a highly specialized physician may have been. Le Francois v. Hobart College, Sup., 31 N.Y.S.2d 200 (1941), aff’d, 262 App.Div. 802, 28 N.Y.S.2d 744 (1941), aff’d, 287 N.Y. 638, 39 N.E.2d 271 (1941).
The record before us provides an adequate basis from which one may reasonably infer the existence of mistake in the execution of the release by the guardian. He had little formal education and was not adept or articulate in the English language. According to the deposition testimony of the attorney who originally represented the plaintiff, the most sophisticated concept used by the guardian in connection with the injury was “concussion”.
As noted by the court of appeals, from the date of the accident through the settlement the plaintiff experienced only minor symptoms. It may reasonably be inferred that when the release was executed the guardian believed the injury was minor, that it posed no risk of complication, that it was temporary in duration, and that his daughter had fully recovered. There is no evidence that anyone, including physicians and the original attorney, disabused the guardian of these beliefs. In fact, the attorney’s legal preparation and his settlement correspondence to the defendants’ insurance carrier belie any awareness that the injury posed any risk of brain dysfunction, much less post-traumatic epilepsy.5 *386This attorney’s belief that the plaintiff had fully recovered from her injury is clearly discernible in his representations to the probate judge at the settlement hearing:
“I am pleased to report to the Court that from all indications, including the final memo from Denver General [Hospital], which is dated a few days ago, she has fully recovered ... and while she had to stay home six weeks to recover, she advises me that she lost no school credits and will, in fact, graduate in good standing from West High School this fall at the age of seventeen years.”
When the record is examined in its entirety, it is apparent that there exists a genuine factual issue on whether the guardian was mistaken about the nature of his daughter’s injury when he executed the release.6 Under these circumstances, summary judgment was inappropriate. See, e. g., Adickes v. S. H. Kress & Co., supra; United States v. Diebold, Inc., supra; Widman v. Ashcraft, 117 Colo. 373, 188 P.2d 889 (1947); Hye v. Riggin, 58 Del. 275, 208 A.2d 513 (1964); Thomas v. Sheehan, 260 Iowa 618, 149 N.W.2d 842 (1967); Frankenheim v. B. Altman & Co., 1 App.Div.2d 200, 149 N.Y. S.2d 11 (1956); Mitzel v. Schatz, supra; Smith v. Chicago Rock Island & Pac. R. R. Co., 525 P.2d 1404 (Okl.App.1973); Warren v. Crockett, 211 Tenn. 173, 364 S.W.2d 352 (1962); Reynolds v. Merrill, 23 Utah 2d 155, 460 P.2d 323 (1969). Similarly, the record fails to demonstrate that the defendants are entitled to judgment as a matter of law. The district court could not properly have concluded that, as a matter of law, the mistake was solely “a unilateral mistake of prognosis” rather than a mistake as to the nature of the underlying injury.
B. The Scope of the Release
The defendants argue that the guardian’s release constitutes a bar to the plaintiff’s claim as a matter of law because its terms are all inclusive and encompass unknown injuries that may later develop or be discovered as well as their effects and consequences.
Although some jurisdictions give effect to the language of a release so as to preclude avoidance even as to unknown injuries, the tendency of the law is to the contrary. II G. Palmer, supra, § 12.22 at 711. Most courts provide for avoidance in appropriate circumstances, such as mistake or lack of intent, despite the presence of language in the release broad enough to cover the claim in question. E. g., Ciletti v. Union Pac. R. Co., 196 F.2d 502 (2d Cir. 1952); Atlantic Greyhound Lines, Inc. v. Metz, 70 F.2d 166 (4th Cir. 1934), cert. denied, 392 U.S. 562, 55 S.Ct. 73, 79 L.Ed. 662 (1934); Casey v. Proctor, supra; Clancy v. Pacenti, supra; Aronovitch v. Levy, 238 Minn. 237, 56 N.W.2d 570 (1953); Landau v. Hertz Drivurself Stations, 237 App.Div. 141, 260 N.Y.S. 561 (1932); Mitzel v. Schatz, supra; Kirchgestner v. Denver & R. G. W. R. Co., 118 Utah 20, 218 P.2d 685 (1950).
In Scotton v. Landers, supra, we held that before a general release, such as here present, will constitute a bar to a claim *387for an unknown injury “it must appear from the circumstances surrounding the transaction that such was [the releasor’s] clear intention.” 190 Colo. at 31, 543 P.2d at 67. Resolution of the intent issue necessarily means going behind the language of the release. If unknown injuries were not within the contemplation of the parties, the release will be set aside. E. g, Scotton v. Landers, supra; Dansky v. Buck, 92 Ariz. 1, 373 P.2d 1 (1962); Aronovitch v. Levy, supra.
Our holding that there was sufficient evidence of mistake as to the nature of the injury so as to preclude summary judgment dictates a like result on the scope of the release. It cannot be argued seriously that, as a matter of law, the guardian intended to release the defendants for future unknown injuries or the later consequences of known or unknown injuries where there is evidence that he was not fully aware of the basic character of the primary injury for which the release was sought and executed.
The judgment of the court of appeals is affirmed.
ERICKSON, J., specially concurs in part in the result. HODGES, C. J., and ROVIRA, J., dissent.. The colloquy between counsel and the court at the commencement of the hearing went as follows:
MR. CARROLL (plaintiffs attorney): “Also, I understand that we are agreeing that the Court will hear this issue today and that the matter will not be submitted to a jury; is that your understanding, or are we going to litigate it before a jury?
MR. PRYOR (defendant’s attorney): “Well, I think the issue of a summary judgment is as it always is with a summary judgment. The Court can rule as a matter of law. The Court could always find that there is some issue of fact, but we would certainly expect the Court to rule on the — and request that the Court rule — on the validity of the release because that is the entire heart of this lawsuit at this point.
*381MR. CARROLL: “We have filed a motion to set aside the release, too, and both matters are before Your Honor, and what I think we are stipulating to is that His Honor’s decision today will be the decision at this level and the trial court level on that particular issue; is that correct?
MR. PRYOR: “I would like — I guess I always look under rocks. I would like to hear the Court’s ruling before 1 make any stipulation as to what I’ll do before I know what the finality of the ruling is. We are here because we think we have a valid release, and we think it is an issue of law as to whether the release is a bar to the claim that is being made.
THE COURT: “This is a summary judgment — I mean, I am just going to rule on the things before me.
MR. CARROLL: “Well, Your Honor, also before you is a motion to set aside the release.
THE COURT: “Yes. Well, I figure that’s a jury question, so I don’t know why we’re talking about juries for.
MR. PRYOR: “The two motions address the same question. We are here to see if this release is any good.
THE COURT: “As I say, all I’m going to decide is what’s before me.”
. The trial court has authority to order a separate trial on the issue of the release preliminary to the principal claim in furtherance of convenience or to avoid prejudice. C.R.C.P. 42(b). However, it did not do so here.
. The line of differentiation will vary with the level of analysis. An intratemporal lobe hema-toma is a collection of blood, usually clotted, within the temporal lobe. It may but need not cause permanent damage to the brain. In contrast, post-traumatic epilepsy is a clinical diagnosis that is based on the presence of seizures and indicates brain dysfunction. See generally 8A L. Chapman, Courtroom Medicine, § 170.00 et seq. (1972); 4 Traumatic Medicine and Surgery for the Attorney, § 806 et seq. (1961). From the standpoint of medical etiology, post-traumatic epilepsy might be characterized as a consequence of an intratemporal lobe hemato-ma. A medical diagnosis of intratemporal lobe hematoma, however, does not subsume a condition of post-traumatic epilepsy. So too, within the framework of legal causation, post-traumatic epilepsy might be characterized as an effect of the underlying trauma caused in an accident. The two conditions, however, are not synonymous for purposes of damages.
. Although the rule of rescission is stated in terms of “mutual mistake,” “courts actually rescind on a finding that the injured party was mistaken, typically that he was unaware of a certain injury. Usually, the other party also will be unaware of the injury, but there is no need to inquire into his state of mind. If he knew or suspected that there was another injury, the case for rescission would be stronger. ... ” II G. Palmer, The Law of Restitution, § 12.22(c) at 712-13 (1978). See, e. g., Casey v. Proctor, 59 Cal.2d 97, 378 P.2d 579, 28 Cal.Rptr. 307 (1963); Denton v. Utley, 350 Mich. 332, 86 N.W.2d 537 (1957).
. In the initial settlement letter of July 28, 1972, the attorney stated that the plaintiff appears to have fully recovered and “upon the present presumption that there is no permanency to *386her damages,” he offered to settle the case for $9,500. The bills for the two hospitalizations in September-October 1970 amounted to $1,457.35, and damage to the plaintiffs clothing and eyeglasses amounted to $147. These amounts were included within the $9,500 offer. The insurance carrier rejected the offer and made a counter offer of $6,114.35, which was the amount for which the case was ultimately settled.
The attorney’s belief that the plaintiffs injury was not serious is further corroborated by his minimal investigation and work-up of the case prior to settlement. In his deposition he stated that he did not file a complaint because he wanted to wait and see if the injury was serious. There was very little contact between him and the Benavidez family from November 1970 until July 1972 when, believing that the plaintiff had fully recovered, he commenced settlement negotiations with the defendants’ insurance carrier.
. The probate court’s approval of the settlement has no effect on the underlying issue of mistake:
“We find no persuasive reason why a minor, whose claims cannot satisfactorily be compromised and released except through court approval, should be more rigorously denied relief than an adult from mutual mistake, simply because the court was laboring under the same mistake.” Scherer v. Ravenswood Hospital Medical Center, 21 Ill.App.3d 637, 639, 316 N.E.2d 98, 100 (1974).