Unless you’re paid by the syllable or intentionally bombastic you should never use symmetrical instead of symmetric, or asymmetrical instead of asymmetric. The only reason to add -al is to convert the adjective to an adverb, as in symmetrically.
Dictionaries seem to have given a pass to adding the extra syllable to these two adjectives. But that is no more correct than turning basic into basical, or ironic into ironical (unless, perhaps, you’re speaking sarcastically).
These examples illustrate that you should only add -al as part of -ally to convert a -ic adjective to an adverb.
Federalist 
OK, first dictionary exception to this rule: Lackadaisical. Why? Perhaps because the root of the adjective (lackaday) is no longer in use, or perhaps because the root is an interjection, not a noun. Though personally I believe the rule should still be enforced and we should use lackadaisic even if it isn’t typically listed in dictionaries
Which brings me to another near-exception: typic has almost universally been superseded by typical, but it is still a dictionary alternative.
English is not logic.
Logic is the art of non-contradictory identification. In other words, if anything that we say leads to a contradiction, it must be abandoned or modified, The vast majority of the words and expressions that we use conform to the laws of logic. Nonetheless, language remains in flux, and we must strive to ensure that the words we use remain true to the rational process of thought from which they were born.
I see what you did there! “Logic” as a counter example in which the “-al” is necessary to make the word an adjective at all. Your reply is very comic and very cynic.
Close: The rule only applies to adjectives that end in -ic, not nouns that end in -ic, which generally require an additional -al to make them adjectives.
I feel that you have a point. If the dictionary does not sufficiently distinguish between two words or forms of a word then choosing one over the other might seem a bit arbitrary. While English( and most other languages) is not logic the grammar must be consistent since these are the rules that speakers use to determine the relations between words in sentences and thus discern meaning. As English’s history,current state, and some of the examples here suggest, the pronunciation and spelling rules of a language need not be homogeneous; in some instances of the exceptions some of you have proposed possible reasons and not a definite cause. Grammar is a series of rules which can be cited when in doubt and upon which one can rely to make unambiguous statements ( the proper/standard grammar of a language). This lack of ambiguity requires that there be neither mixing of “grammars” nor inconsistencies. So grammar is like a system of equations in 3 dimensional x1.x2.x3 ( or any dimensionalx1….. xn) space.The space itself may also contain the words of the language and both grammar and words may be mapped to meaning. The equations must be consistent for meaning to be discerned from them (consistent grammar rules) but we may have more freedom in choosing points in rest of the space and it may even be the case that some points which are words might map to the same meaning as another point/word because for many languages the vocabulary has some degeneracy ( I am trying to use the term degeneracy as it would be used in physics to describe two entities with the same energy and different states)
So is a ball symmetric and spheric, symmetrical and spherical, or symmetric and spherical?
I tend to like the sound of the last pair the best, although I can find no reference giving a real reason for that (Webster’s merely lists spheric as archaic, I guess like typic).
Good example. I agree spheric sounds especially archaic, but I still prefer it over spherical.
I guess my preferences tend to be for the minimalist and conservative — whether we’re talking about words or government!
-al only works with ECONOMIC and ECONOMICAL. These two cause problems to the learners of English as they can make a stupid mistake by not understanding the difference in meaning, e.g. economic crisis; economical car.
Used as adj. before a noun
The bacteria exhibit symmetric pattern
Used as stand alone adj.
The pattern of the bacteria is symmetrical
This sounds like a plausible rule of usage. Can anyone provide further reasoning or authority for this?
Symmetrical is modifying “pattern of the bacteria” correct? So in what sense is symmetrical a stand alone adj?
what about identic?
Forgive me for resuscitating this debate, but there are plenty of good reasons to use “-ical” instead of “-ic,” at least on certain occasions. Look at the distinction between “historic” and “historical,” formed on the same lines. The suffix “-ical” forms secondary adjectives off of adjectives already ending in “-ic.” Thus “comical,” “musical,” “philosophical,” “physical.” These words convey important distinctions in meaning: “comical” means something different from “comic,” even though they are sometimes interchangeable. “Philosophical” is standard usage, while “philosophic” or “physic” (used as an adjective) would strike the modern reader as odd.
I do mostly agree in this specific case that “symmetric” is superior to “symmetrical,” but I would also note in passing that the formation of “symmetrical” is analogous to that of “geometrical,” which for a long time would have been more standard than “geometric.” But “symmetrical” is not obviously wrong in the way that other bloated extra-long formations are. And I confess that, to my ear, “asymmetrical” sounds better (more symmetric, perhaps), than “asymmetric.”
Historic and historical, while both adjectives, appear to actually be two different words since they have distinct meanings.
NB: The fact that something sounds better may be due to familiarity, which doesn’t mean it’s correct or ideal.
Granted, there may be a good rule, perhaps like that proposed by @Nhan Le above, that explains when and why the “-ical” form of “-ic” adjectives should be used.
For example, can you articulate the difference in meaning between the adjective forms of “comic” and “comical?” I can only see a difference in usage along the lines of @Nhan Le’s rule.
Also note that some of your examples — physic and music — are nouns, never adjectives, and therefore the rules here don’t apply.
In some uses, “historic” and “historical” have distinct meanings. In other uses, they are interchangeable. In most circumstances, though, a modern user would always use “historical.”
“Physic” and “music” are indeed adjectival forms. I have double-checked this in the OED. They are never used as adjectives today, because they have been supplanted by “physical” and “musical.” But those terms were formed along the exact same lines as “historical,” “geometrical,” or “comical.” The difference is that “physical” and “musical” have been historically successful enough to completely displace the “-ic” formations as adjectives, precisely because the “-ic”/”-ical” distinction is so useful.
The comment about “asymmetrical” sounding better was intended at least partly as a joke: the accent falls squarely on the middle syllable, so that “asymmetrical” is pronounced symmetrically.
One important thing about both “symmetrical” and “asymmetrical” is that their English usage is actually older than the use of “symmetric” and “asymmetric.” The OED lists the first (recorded) use of “asymmetrical” in 1690, by Robert Boyle; “asymmetric” appears in 1878, and slightly earlier in the technical discourse of chemistry. So here the “-ical” usage, due to the peculiarities of English formations based on French words, is older, and would presumably have been thought more correct at the time of the new formation.
Similarly, the first use of “symmetrical” is recorded by Samuel Johnson himself, who could probably make this argument far better than I, in 1751. “Symmetry” appears only in 1796, again in technical discourse.
This is an interesting conversation, and I wouldn’t presume to pronounce one form or the other as correct in all situations. But the historical evidence of these words and other similar words does at least show that both uses are valid. A case could even be made, from the history of use, that the shorter “-ic” versions originated as scientific jargon, and neglect the principle by which secondary adjectives use the “-ical” ending.
The major usage distinction I can point out between “comic” and “comical” deals with drama. One would say that a play like “Measure for Measure” is “comic” as opposed to “dramatic.” You could not say the same thing with “comical.” A comic work is a work that intends to be funny, whether or not it succeeds; if a work is comical, it has succeeded in being funny. I suspect that distinction is intuitive to users of these two words. One might also use “comical” to refer to something that is odd or unusual, though this is a somewhat outdated 19th-century application; one would never have used “comic” in the same sense.
Thank you for the illuminating background. Etymology is certainly a compelling argument. Can you elaborate on the derivation from French that produces “-ical” forms?
And thank you for the interesting discussion.
As for the derivation from French, most English words that use the “-ic” suffix passed through French. The “-ic” was originally a Latin suffix, but it’s most familiar as the French “-ique,” as in “magnifique.” Instead of inheriting these words directly from Latin, we tended to inherit them after the French had modified them in subtle ways. A particularly fertile field for “-ic” terms was the science of chemistry (which also produced the first recorded use of “symmetrical” in English). This also originated in the practice of French chemists. Many of these are still current, so we talk about sulfuric acid (originally “sulphuric”) or chloric acid, and the suffix distinguishes these from sulphurous or chloric acid.
Before about the sixteenth century, English writers imitated the French “-ique” more closely, using spellings like “logike,” “rhetorike,” even “ethyque” for “ethic.” Some of these forms hail from the Greek suffix “-ikos,” passing through Latin and then French to reach the English. It was in the titles of learned treatises that these words first acquired their modern form, especially in the name of sciences like “physics,” “dynamics,” “mechanics,” “metaphysics,” “mathematics.” Some of these smoothed out even further in popular use, or at least it became acceptable to use them in the singular. Other formations along these lines are still used in the plural: “gymnastics” or “politics,” for instance.
The “-al” suffix, which combines with these various uses of “-ic” to form the “-ical” suffix we’re discussing here, similarly passed from the Latin “-alis” to the French. Early French used both “-el” and “-al” in similar ways, and often the use of “-al” was a conscious imitation of Latin. English adopted this shift as well, so that “mortel” became our “mortal,” for instance. After this usage caught on in English, countless words along the same lines came into use, some adopted directly from French or Latin and some new formations. “General,” “special,” “occasional,” “professional”– the list is almost endless. It was after this usage became standard that “-al” would be tacked onto adjectives, to form secondary adjectives like “philosophical” from “philosophic,” “poetical” from “poetic,” and indeed, much later, “symmetrical” from “symmetric.”
It is partly this intermingling of Latin and French influences that makes this particular topic so complicated. But it also makes for a nice springboard into these kinds of arcane digressions.
Fascinating; thank you for the detail! I see the origins of the -ic and the -al, but based one your explanation it sounds like the compounding of the two was not etymologic but rather an unnecessary muddling that occurred only in English?
Good point; that strikes to the heart of the matter, and it shows why a discussion of what seems like a pretty straightforward English point gets so complicated so quickly.
You’re right that the compounding of the two was not rational or inevitable, but almost nothing in the English language is. The great majority of the words we use were formed irrationally, by strange maneuvers, and all we can really do is to try to track the way those formations occurred. It doesn’t really speak to the correctness of a certain formation.
For one thing, the idea of “correctness,” in a grammatical or lexical sense, wasn’t current when these words were being formed. In the late Renaissance there was a vague desire among cultured writers to imitate the classical Greek and Latin writers, leading to the importing of more Greek and Latin words (sometimes doing strange and terrible things to them in the process) and the formation of other words along Greek and Latin lines. The “-tion” suffix, for instance, originally of Latin use, started getting shoved onto any number of words without any Latin antecedents, words from Germanic languages, for instance. Our dictionaries now are crowded with hundreds of words formed by this method, and they are historically as muddled as you can get.
Writing around the period of the “-ic” and “-al” developments, Shakespeare coined about two thousand words, many of which we still use. If there wasn’t a word for what he wanted to say, he would make one up with no apologies, and there’s a good chance it would survive five hundred years later. He could do this because English was not codified–there were no organized, monolithic standards of grammar, syntax, or vocabulary. The first English dictionary didn’t appear until the 18th century, long after all these developments. So Shakespeare could make up a word like “assassination,” which is etymologically completely irrational, but practically useful, and has persisted on those grounds. For that particular word, he took an Arabic root, its spelling already corrupted by transliteration into the Latin alphabet, and tacked on a Latin suffix. Absolute madness, but there was no one to tell him not to do it.
Similarly, the vogue for French words that came into English (words like “vogue”, I suppose) began not for linguistic reasons, but for historical ones. The Norman Conquest of the eleventh century placed parts of England under French domination, and led to the intermingling of English and French culture and language. Even independent of these major events, though, English is a voracious language, almost an imperialist language: if it sees something it wants, it adopts it, regardless of whether it makes an sense. This is why we have words from Greek, Latin, French, Arabic, and countless other languages mixed with the original Germanic content of English. This is why we often have eighteen or twenty words that mean the exact same thing, but entered the language by different routes.
Now the situation is even more complicated, because there are multiple major varieties of English: American English and British English, of course, are the major ones, but Canadian and Australian English show important differences. And English has become something of a lingua franca, with people all over the world speaking at least some English, and modifying it as well, so that various forms of quasi-English pidgins and patois exist pretty much everywhere in the world. Language is messy and basically entirely irrational.
One last thing. The French codified their language around the nineteenth century, in a pretty successful attempt to keep the language “pure” for various cultural, literary, and nationalist reasons. Even now, French is an organized language, the grammar is standardized and the vocabulary relatively stable (though new intrusions by technological terms are changing all languages). French, and other languages, have organized systems of word endings and grammar, some of which were set down arbitrarily by government councils in the time of the codification. English doesn’t have anything like this, but I don’t think it’s a bad trade. We have, instead, a massive vocabulary, often many times the size of other languages, along with the capacity for tremendous precision of meaning and delicate connotation. The price we have to pay for this is a kind of linguistic anarchy. These kinds of debates about specific words tend to open up to highlight these remarkable features of English. All the same, you are absolutely right; we are Muddled with a capital M.