According to the OED, Webster's, and even answers.com, all three of the definitions here:
- truthful, factual.
- I will believe him as soon as he offers a valid answer.
- acceptable, proper or correct.
- A valid format for the date is MM/DD/YY.
- Do not drive without a valid license.
- related to the current topic, or presented within context, relevant.
are wrong. Here is the entry from Webster's Unabridged:
[MF or ML; MF valide, fr. ML validus, fr. L, strong, fr. valere to be strong --- more at WIELD]
1 a : having legal strength or force : incapable of being rightfully overthrown or set aside : sanctioned or authorized by sovereign temporal or spiritual power
b : conforming to conditions essential to sacramental efficacy
2 a : well grounded or justifiable : applicable to the matter at hand : PERTINENT, SOUND
b of an inference : correctly derived from its premises
specif : true in terms of the logical principles of the logistic system to which the inference belongs
3 a : able to effect or accomplish what is designed or intended : EFFECTIVE, EFFICACIOUS
b : capable of measuring, predicting, or representing according to intention or design
--- compare RELIABLE
4 a : STRONG, POWERFUL
b : HEALTHY, ROBUST
5 a of a taxon : based on distinctive characters of recognized importance : founded on an adequate basis of classification
also : validly published
b of the publication of a taxon : effective and accompanied by a description of the taxon or a reference to a previous description
SOUND, COGENT, CONVINCING, TELLING may be compared with VALID in being applied to arguments, reasonings, principles, ideas which have such force that they compel acceptance. Both VALID and SOUND imply that the force is inherent in the rationality of the thought apart from its presentation. A VALID argument or principle is supported either by objective truth or a generally accepted standard or authority
although a VALID concept may have certain especially psychological limits
SOUND, which may be applied to both persons and concepts, implies avoidance of fallacies, insufficient evidence, and hasty conclusions, and stresses solid foundation in fact or in reason or both, as well as the habit of clear and deliberate thought, often with an admixture of shrewed practical sense
COGENT and CONVINCING apply to ideas (less frequently, to persons) compelling mental assent, but COGENT stresses a force resident in the argument or reasoning, as inevitability or conclusiveness, as well as succinct and lucid presentation
whereas a convincing argument, speaker, or book may convince by either sound reasoning or by skillful selection and presentation
CONVINCING is often applied to fictional creations having the flavor of reality
TELLING suggests an immediate and crucial effect striking at the essence of the point, idea, or sentiment to be conveyed regardless of the validity of the cause
and here is the OED's entry:
valid, a. (and n.)
1. Good or adequate in law; possessing legal authority or force; legally binding or efficacious.
- 1571 Reg. Privy Council Scot. II. 95 Seing his said tak is valide and sufficient in the self. 1651 HOBBES Leviath. I. xv. 72 The nature of Justice, consisteth in keeping of valid Covenants. a1688 CUDWORTH Immut. Mor. (1731) 2 Whatsoever is decreed and constituted, that for the time is Valid, being made so by Arts and Laws. 1726 in Nairne Peerage Evidence (1874) 36 Declareing if I do not exerce these faculties in my own time these presents shall remain a valed evident albeit not delivered by me. 1769 ROBERTSON Chas. V, IX. Wks. 1851 IV. 315 This strange tribunal founded its charge upon the ban of the empire, which..was..destitute of every legal formality which could render it valid. 1786 BURKE Art. agst. W. Hastings Wks. II. 90 A claim, which they determined not to comply with but in return for the surrender of another equally valid. 1844 H. H. WILSON Brit. India III. 257 Those, who held rent-free lands by titles that might be declared valid. 1878 JEVONS Primer Pol. Econ. 128 According to law, deeds, leases, cheques, receipts, contracts, and many other documents are not legally valid unless they be stamped.
b. Eccl. Technically perfect or efficacious.
- 1674 J. OWEN Holy Spirit (1693) 235 So as that the Call to Office should yet be valid. c1680 BEVERIDGE Serm. (1729) I. 28 Not but that the ordination is valid. 1876 MELLOR Priesth. viii. 361 No ordination is valid unless there be in the recipient of orders what is termed in the Church of Rome an habitual, or, at least, a virtual intention.
2. Of arguments, proofs, assertions, etc.: Well founded and fully applicable to the particular matter or circumstances; sound and to the point; against which no objection can fairly be brought.
- a1648 LD. HERBERT Autobiog. (1764) 138 The whole face of Affairs was presently changed, insomuch that neither my Reasons, nor the Ambassadors.., how valid soever cou'd prevail. 1692 BENTLEY Boyle Lect. iv. 115 He may admit of those Arguments as valid and conclusive. 1717 PRIOR Alma I. 416 For when One's Proofs are aptly chosen; Four are as valid as four Dozen. 1766 PITT in Almon Anecd. xxix. (1810) I. 432 The excuse is a valid one, if it is a just one. 1803 WELLINGTON in Gurwood Disp. (1835) II. 164 Reasons which I thought valid but which I do not think it necessary to communicate to him. 1859 MILL Liberty ii. 36 An objection which applies to all conduct, can be no valid objection to any conduct in particular. 1881 WESTCOTT & HORT Grk. N.T. Introd. §46 A generalisation obtained from one book would be fairly valid for all the rest.
b. In general use: Effective, effectual; sound.
- 1651 HOBBES Govt. & Soc. ii. §7. 23 If yet to words relating to the future, there shall some other signes be added, they may become as valid, as if they had been spoken of the present. 1774 REID Aristotle's Logic ii. §2. 183 This same et cætera..shall in any future time shew a good and valid right to a property in the subject. 1824 BYRON Juan XVI. xxxv, The effort was not valid To hinder him from growing still more pallid. 1860 MANSEL Proleg. Log. (ed. 2) 22 The only valid method of investigating the relation between thought and speech. 1875 GEO. ELIOT in Cross Life III. 253, I should urge you to consider your early religious experience as a portion of valid knowledge.
3. Of things: Strong, powerful. Now arch.
- 1656 BLOUNT Glossogr., Valid, strong, mighty, puissant, able. 1667 MILTON P.L. VI. 438 Perhaps more valid Armes, Weapons more violent, when next we meet, May serve to better us. 1807 CRABBE Birth of Flattery 109 So on a dream our peasant placed his hope, And found that rush as valid as a rope. 1887 BROWNING Parleyings Wks. 1896 II. 692/2 What beseems a king who cannot reign, But to drop sceptre valid arm should wield? 1891 Cornh. Mag. Nov. 493 In addition to the strong jaws..there are three exceedingly valid hooks.
b. Of malt liquor: Unduly thick. Obs.
- 1742 London & Co. Brewer I. (ed. 4) 38 They also keep it from running into such Cohesions as would make it ropy, valid, and sour.
4. Of persons: Sound or robust in body; possessed of health and strength. Also said of health.
- 1652 GAULE Magastrom. 139 The more valetudinary have commonly been the more vertuous; and the more valid, the more vitious. 1708 MOTTEUX Rabelais (1737) V. 232 Thanks to Jove's Benignity you're valid. 1757 E. GRIFFITH Lett. Henry & Frances (1767) IV. 137, I much fear his excessive Grief may injure his Health, which is not very valid, at present. 1879 SALA in Daily Telegr. 12 June, When he was a valid man he may have had many a boxing bout with Shaw the Life Guardsman. 1899 Daily News 1 Dec. 7/1 The Boers have evidently put every valid male into the field.
b. Of the mind: Sane, strong. rare.
- 1854 EMERSON Lett. & Soc. Aims, Poet. & Imag. Wks. (Bohn) III. 139 The restraining grace of common-sense is the mark of all the valid minds.
5. As n. A person in good health. Opposed to INVALID n. 1.
- 1882 Pall Mall G. 20 Sept. 5 Kuristen and valids may alike thank Dr. Yeo for a series of highly interesting and instructive Essays.
What is the usual procedure in such a case?