Scalia's major contribution to what he called "the science of statutory interpretation" was his doctrine of "textualism". I'll let him describe in his own words:
A text should not be construed strictly, and it should not be construed leniently; it should be construed reasonably, to contain all that it fairly means...while the good textualist is not a literalist, neither is he a nihlist. Words do have a limited range of meaning, and no interpretation that goes beyond that range is permissible. (Common-Law Courts in a Civil Law System, 98-99)This rhetoric was the foundation for an extraordinary number of Scalia's arguments and opinions (except when he conveniently abandoned it completely - see also Obamacare). It will likely be associated with his name for decades to come, precisely because he made such a big show of owning it; he even wrote an entire ridiculous book about it. And it is remarkably, empirically stupid.
One basic problem here is that Scalia's textualism is mostly just a way of begging the question. Ask him how a text should reasonably and fairly be interpreted, and he replies that "it should be construed reasonably, to contain all that it fairly means". This sort of empty tautology gives us no insight into how interpretation works, no methodological approach for pursuing it. It's nothing more than a variation on the famously nonsensical pun of Alice in Wonderland's Queen of Hearts: "Sentence first - verdict afterwards."
Textualists, of course, would contest this critique by insisting that Scalia's assessment of fairness and reasonableness are ultimately grounded in what he calls "the objective indication of words".
Unfortunately for Scalia's "science" of jurisprudence, this notion that words have some "objective indication" is in direct contradiction with the actual science of linguistics. A full century ago, Ferdinand de Saussure - universally acknowledged as the father of modern linguistics - was quite plain on this point in his seminal text, Course in General Linguistics:
First principle: the sign is arbitrary
No one disputes the fact that linguistic signs are arbitrary...the principle stated above is the organising principle for the whole of linguistics, considered as a science of language structure...any means of expression accepted in a society rests in principle upon a collective habit, or on convention...It is this rule which renders them obligatory, not their intrinsic value.There is, that is to say, no "objective indication" of words, no actual or indipsutable meaning that you can appeal to when trying to argue what is "reasonable" and "fair"; words just mean whatever we decide that they mean.
As de Saussure notes, the "consequences that flow from this principle...do not all appear at first sight equally evident"; but for textualism, the consequence is that Scalia's entire jurisprudence is thoroughly invalidated as a matter of science. He can only save his argument from utter tautology by resting it on a foundation of objective linguistic meaning that does not actually exist. If he is right, a hundred years of linguistics is somehow entirely wrong, and all of this mysterious progress we've made in understanding how language works some kind of inexplicable illusion or stroke of sheer luck.
Scalia's textualism flatters the sensibilities of people who want to think of themselves as reasonable and fair without digging into what that actually means. It props itself up on just-so claims about the true meaning of words that are entirely and directly in dispute. For these reasons, textualism will remain forever popular as a rhetorical bludgeon - a dignified veil over the stubborn bluster of Scalia and his heirs. But no one else should take this nonsense seriously, or pretend that he contributed anything more than a ridiculous brand of jurisprudence and a lifetime of terrible opinions.