The argument by John that the case between his company and Beth should be ruled in company's favour based on past rulings of similar case is valid. This is because the common law system is recognized by various nations and may be applicable in this case. This system argues that it's not fair to treat similar cases differently on different occasions. Moreover, an ideal common law court considers past precedential decisions of courts that are relevant. However, if the court discovers that the present dispute is basically different from all the past cases, judges have the right to make rulings by creating precedent.
As a matter of fact, it is not a must for the judge in this case to make a ruling similar to those of previous judges. Beth may argue that common laws are not precedent bound and the facts of both cases must be similar. Moreover, court decisions are binding only in a certain jurisdiction and some courts posses' higher powers as compared to others. There exists considerable complexity between common law and other laws such as regulatory, constitutional, and statutory law. The research and analysis of facts in each case is quite different and thus the law in each case should be determined differently. It is difficult to ascertain the gathered facts in relation to past facts hence common law is hardly practical in most cases.
On a similar note, decisions of higher legislatures carry more weight as compared to those of lower courts and earlier cases. In addition, the rulings made in earlier jurisdictions may have been unfair following lack of evidence or law malpractices by the previous judges. Considering that common law is not coded like the other systems of law, it may be messy since it's a subjective decision that is depended on the preference of each individual. Thus, Beth may use these arguments to oppose the application of common law in this case.