Are the critics right? Is there scant evidence for universals? The right answer is that it all depends what you mean by ‘universal.’ If by this you intend a Greenberg Universal (GU) then it might be right (in fact, as you will see below, I think it should be right). If by this you mean a Chomsky Universal (CU) then you are not likely right. There is a big difference between these two and the empirical success of GG rests on keeping them firmly distinguished. Why? Because a priori there is little reason to think that there are many GUs out there. There may be a few, but the standard GG universals if understood as candidate GUs are not likely among them. When critics of GG argue that it’s hard to find universals expressed in the world’s many languages, they understand ‘universals’ as GUs. And here they may well be right! However, as GG commits itself to CUs and not GUs it requires quite some ancillary argument to conclude from the absence of GUs to the non-existence of CUs.
Indeed, from a perfectly normal “scientific” point of view, we should not expect to find many GUs. What do I mean? Well, think of the analogues of GUs in a real science, like Newtonian mechanics. We observe that bodies fall. We ask what makes bodies fall. We propose that bodies “fall” because of gravitational attraction. In particular, there is a force G that causes bodies (i.e. masses) to attract. Larger masses exert a stronger pull than smaller ones. Thus, bodies much smaller than the earth, say a ball, will “fall” in the sense that the mass of the earth will more strongly attract the mass of the ball than vice versa. This will make it appear that the ball “falls” to earth when it is released (rather than the earth “falls” to the ball). That’s the story, and a good one it is, though we now know that it needs amending, especially if the ball is travelling near the speed of light. At any rate, what’s this have to do with GUs?
Well, is it indeed phenomenologically accurate that when we observe falling bodies in the wild we observe them acting in accord with Newton’s law of gravitation? Nope. Note even close. A leaf drops from a tree. Does it appear to fall in accordance with the law of falling bodies. Not on your life. Drop a ball into lake and see how long it takes to hit bottom (or if it hits bottom at all). Does it appear to drop in accordance with the law of falling bodies? Nahh! Or take a body that is electrically charged and drop it in an electrical field and see if Newton’s law suffices to describe its trajectory. It doesn’t. What’s the right conclusion: that gravity is not a cause of falling bodies, that things don’t universally attract (i.e. fall)? Not on your life. Why?
Here’s the conventional wisdom. We understand that the law of falling bodies is not intended as a description of what we see outside our window. It describes one relevant force in causing what we see. And this force in complex interaction with many other factors, causes observed physical behavior. Thus, we know that shape matters (not just mass) if the object is not dropped in a vacuum (and vacuums are pretty rare out there in the real world). We know that the consistency of the space into which an object drops also matters (less frictional resistance in air than in water and less in air than in mercury). We know that electrical charges exert forces on electrically charged objects and so this, as well as mass, can effect a falling object’s trajectory. If the object is small enough, then other factors may intercede as well. If shaped a certain way, drop an object into water and it will float rather than fall. So many factors stand between dropping and falling and nonetheless gravity does explain why bodies fall.
What’s this mean? It means that whatever the law of falling bodies is, it is not a description of what we see when we look at the world outside our window. In other words, it is not GUish. It is not a description of the immediately phenomenal world, but a proposal about one of the fundamental forces that act on bodies and this force is (often) an important causal factor in determining how bodies that we see fall actually do fall. Pure expressions of the law take careful experimental set up. Indeed, we must control for many other factors, before we can “see” gravity’s effects.
There is an excellent discussion of just how complex this is in Cartwright (here, chapter 4). I have discussed her main points in previous posts (see here). For current purposes, Cartwright makes two very important observations. First, that it takes a lot of work to hook a law up to observation. This is what a good experiment does. It establishes a way of observing the effects of abstract non-observable features to visible effects. It creates a “nomological machine,” a way of hooking up the underlying capacities to surface regularities. And, this is the important part:
There is no fact of the matter what a system can do just in virtue of having a given capacity. What it does , depends on its setting, and the kinds of settingsnecessary for it to produce systematic and predictable results are very exceptional (73).
So, gravity can be seen in action, but only if we arrange things very carefully! And if this is true of gravity, why should it be less true of a principle of UG? Of course it might be different in the mental sciences, but it might not be, and assuming that linguistic “laws” (aka principles of UG) must be apparent to inspection in the wild is little more than methodological dualism (a real no-no).
Returning to the main topic, GUs are typological generalizations. They describe (and are intended to describe) generalizations thought to be observable across languages, surface generalizations. Why are we surprised that not many can be found? Why are we surprised that the UG principles proposed are not “surface true”? Why should we expect the visible surface properties of language to express the underlying grammatical forces at work any more than we expect the phenomenological observables of real world events to distinctly manifest their underlying causes (e.g. the law of gravity in bodies observed falling around us). We don’t in the latter, and shouldn’t in the former. Which brings us to CUs.
Chomsky understood universals to be properties of FL, FL being the specifically linguistic contribution that minds exploit to build language particular Gs. From the get-go, these were understood to be quite abstract, and to not be inducible from the simple inspection of the surface properties of sentences. Thus, CUs were not intended to be surface true, anymore than gravity is. Thus, the absence of GUs does not imply the non-existence of CUs any more than the phenomenological inadequacy of the laws of gravity to describe what happens when any object falls any time anywhere invalidates Newton’s theory of gravity and its explanation for the law of falling bodies.
IMO, none of this is or should be controversial. I mention it because it seems easily forgotten. Linguists (or many of them) are currently quite skeptical that we have discovered any universals. But this is because many forget the distinction between GUs and CUs. Doing so leads to skepticism precisely because there is every reason to believe that universals understood as Greenbergian objects are not (and should not be) thick on the linguistic ground. Thus, when critics point out that such GUs are not pervasive we should agree and say that nobody thought (or should have thought) they would be. And then loudly repeat that GUs are not CUs and CUs is what we are looking for.
Why the warning? Because, it seems to me that typological work invites the inference that linguists are on the hunt for GUs and that GGers agree with critics of the Chomsky program that universals ought to be understood as GUs. But this is a mistake, one that misunderstands what GG is about. To repeat a venerable theme: GG takes the object of study to be the structure of FL/UG, not the properties of languages. These latter are interesting to the degree that they illuminate the former. And there is no reason to think that linguistic principles, any more than any other scientific principles, will be visible in the data used to investigate them.
Let me make this point another way. IMO, there is no way that something like FL/UG does not exist (see here and here for a defense). That FL/UG exists is a virtual truism. What’s in FL/UG is not. Thus, what’s up for grabs is the fine structure of FL/UG, not whether it exists. Here’s another triviality: language exhibits the properties of FL/UG only in interaction with many other adventitious linguistic factors, many non-linguistic cognitive factors and probably much else (like the weather, time of day, and who knows what else). This means that we expect the fine structure of FL/UG to be hard to discern and we do not expect it to sit out there waiting to be spotted by (even careful) observation.
In fact, I would go further (as you knew I would). I suspect that the only really good way to argue for a CU is via something like a POS argument. Looking at lots of languages and Gs might be helpful (see here), but if you want to zero in on potential candidate universals, there is nothing like a POS argument. Why? Because, POSs limn the borders of the grammatically possible. That’s what’s so nice about them. Inductive surveys of many Gs cannot do this. POSs are the linguistic analogue of Cartwright’s nomological machines. They afford the most direct access to CUs, and for those interested in FL/UG, CUs are the principle objects of interest.
So be careful out there. Languages and their fabulous intricacies can be confusing. It’s not that hard to mistake Greenberg Universals for Chomsky Universals, and it’s a slippery slope from there the dreaded vice of Empiricism (and its concomitant horrors (e.g. connectionism). So watch your step when you go into the field.
 As I’ve noted before, there is a tendency to understand universals as patterns in the data waiting to be revealed. Finding universals is then roughly a problem in signal processing in which the judicious use of statistical techniques will find the signal in the often very noisy noise. This conception understands universals as GUs. It is not the right model of a CU. For discussion see here. Incidentally, mistaking GUs for CUs will eventually lay low Deep Learning/Big Data approaches to language. The latter count on the fact that all universals will be GUs. If this is false, and it is, then such approaches cannot succeed, and so they won’t. Of course it will take time for this to become evident and by then another fad will sweep the Empiricist world.