Richard Posner's article "Legal Reasoning From the Top Down and From the Bottom Up: The Question of Unenumrated Rights" begins with a description of what he views to be two distinct types of legal reasoning. (1) Top down reasoning consists of jurists and legal theorists creating theory about law or certain laws and then proceeding with this framework to answer all future questions. (2) Bottom up reasoning is the idea that all decisions should be based in text (Bork!) or existing case law.
Posner rejects Dworkin's theory of law and, more broadly, all "ambitious" top down approaches because they selectively prune cases that do not support their view and base a broad theory on a few, often imperfect, examples. He believes any holistic approach would have difficulty garnering public favor because it is likely to be too expansive. Such a broad conception would not be able to answer specific questions and thus would upset those who felt their rights were trumped by an unsubstantiated theory. Posner asserts that this is why "the cautious jurist uses the clause by clause approach."
Posner also rejects several arguments in support of Roe. The 9th Amendment, he argues, could not possibly be the basis of permitting abortions because if such stretches of the 9th were permissible the ability of any criminal to argue that a law is unconstitutional would be limitless. He also finds the claims of sexism in anti-abortion laws to be uncompelling and thus rejects the Equal Protection claims of the feminist movement. Finally, Posner flatly rejects Dworkin's argument that one's understanding of prenatal life is a religious value and thus protected by the Free Exercise clause because such a claim ultimately puts the religious belief of Dworkin above pro-lifers. If the court allows abortions then it is knowingly violating the religious beliefs of those that believe life begins at conception by not classifying abortion as infanticide. Posner further states that the plethora of weak textual arguments put forth by proponents only serves to show the absence of textual legitimacy for their claims.
While he is quick to argue against broad top down decrees of unsubstantiated legal theory, Posner also find the bottom up approach to be far too limiting on the ability of judges to interpret the law. Posner asserts that American jurisprudence must "preserve a role for conscience." He answers critics of this approach who may find such moral interpretation to be undemocratic and dangerous by saying that all decisions must be based in fact and deference to past decisions. Posner rejects the conventional principles of legal reasoning because "they miss the vital essence of legal growth and insight." He concludes by remarking that when we come upon an area of law that is not addressed by the Constitution that we must trust the ability of judges to gauge the moral and social implications of their decision. Posner believes that this supports his ability to defend Griswold and Justice Holmes' decision in Lochner while concurrently rejecting the arguments in support of Roe.