Perhaps the most important intellectual point law students must learn to be effective in the profession is the difference between the descriptive and the normative. It is easy. The former refers to what is; the latter relates to what ought to be. These are fancy words for simple concepts. You don't have to use the jargon to benefit from the principle.
Statements such as "the defendant will be liable to you for the defective product that injured you" or "the government probably will be liable to you for violating your privacy rights" are descriptive. They can be true or false. They are in part a prediction about the likely litigation outcome. If you visit a dozen competent and ethical lawyers, you should receive more or less the same opinion from almost all of them. There may be varying degrees of optimism to pessimism.
Statements such as, "a company should not be liable to a consumer for a defective product, because losses should remain where they fall" or "the government should not be compiling a file about you" are normative. They are neither true nor false, because they constitute arguments. They might be persuasive; they might not be. Policy-makers could accept them and enact statutes accordingly, or they could reject them in favor of alternatives.
More than a century ago, English philosopher G.E. Moore gave the name "the naturalistic fallacy" to the tendency to assume that the descriptive automatically determines the normative. Philosophy turns out to be practical. (Professors continue to debate whether Moore extended the argument about error beyond its logical limit, but that is more esoteric than need detain us here.)
Most people fail to distinguish as Moore suggested, between what is and what ought to be. Their mistake is understandable. It is human. They have sincere emotions and political commitments. As a consequence, they regard their own beliefs as the best. They assert a claim as fact not opinion, since they want it to be such.
The conflation of descriptive and normative leads to unnecessary disputes in public discourse. Or, even if they are necessary disagreements, the conflict comes to be concentrated on the wrong issue. Someone declares that there is a racial disparity, for example, and someone else misconstrues the speaker as endorsing the discrepancy. It may be, though, that the intent is to decry the problem.
The reason a law student is required to analyze what the law is, even as she argues about what it should be, is that her client retains her with the expectation she is expert. She holds herself out as being able to foresee the future. She cannot be guessing.
In the classroom, I generally correct students who open, "I believe X" or "I feel Y." I am disinterested in their heartfelt beliefs and intense feelings, because the judge before they appear also will be (or should be). A skeptic might say I am instilling an ideology. It is, ironically, to be anti-ideological. That defines a profession in which one represents others. An especially responsible member of the bar will take on the occasional client with whom she has nothing in common, someone whose background is abhorrent.
In my classes, we do pause from time to time, however, to deliberate over what students care about. It is good to step outside the system now and then.
Beyond the classroom, an individual who is being trained to serve clients needs to be able to explain doctrines in a manner that enables good decision-making. An attorney who is unable to be objective will not serve her cause.
A lawyer who substitutes her hopes about the law for the reality of the law increases the risk of adverse results. She is hired to draft a contract that will stand up to challenge or to win a case. She is not paid to advance an idiosyncratic hypothesis except in the instance when the client appreciates what they are inviting.
Among the most difficult tasks a lawyer performs is telling a client that the client's great business idea will not work, because it regrettably is illegal. Or the client's preferred line of argument has already failed to impress the courts, rendering it useless. It is all the harder to do that if the lawyer herself happens to agree the idea or argument should be deemed worthwhile. A talented lawyer will consider all creative options. A wise lawyer has the discipline to recognize what is not feasible.
None of this is to crush idealism. A champion of change has all the more need to perceive the world as it is, as accurately as practicable. That is the pre-requisite to progress. Advocacy for change, if it is to be legal reform, proceeds through a set of maneuvers.
Legal reasoning is not only about rules. It also is bound by rules. There are a set of accepted moves, as others have observed, comparing law to chess or basketball. Technical skill depends on knowing the range of legitimate plays: a knight cannot move in a straight line; the ball must be dribbled or passed but cannot be carried. You could say, "a knight should be able to move like a rook," or "traveling should not be penalized," but the game would no longer be the standard version of chess or basketball, respectively. It could be an interesting game of its own, but that is another matter.
Allow me to close as a law professor usually does. Ever since the Sophists, teachers of rhetoric -- and that is what a law professor is, an instructor in argument -- have been accused of promoting contradictory views. I regard that indictment as complimentary. A scholar who is honest and open-minded is indeed willing to entertain and test multiple hypotheses.
I deliberately subvert what I have said above. I do not count myself among those "positivists" who would separate law and justice, insisting that law is what it is regardless of whether it is right. The distinction between descriptive and normative is critical. But it is not absolute. Scarcely anybody talks about what the law is without also thinking about what the law ought to be. What makes the best lawyers and judges is that they are aware they are doing so.
I strive to see the world as it is, even as I imagine it as it should be.