下载掌阅APP，畅读海量书库
立即打开
In contrast to logic，there is common sense，or still better，the spirit of reasonableness.
——Lin Yutang
If one searches for the meaning of the word “reasonableness”，the most common results are “sensible” and “of sound judgment”.The terms “fair”，“appropriate” and “moderate” also appear.
To be reasonable is to be sensible and to exercise sound judgment.
A critical aspect of reasonableness，certainly so far as law is concerned，is objectivity.A person is judged not by his own standard or expectation.A person does not act reasonably simply because as he does an act，he exercises his judgment and thinks that his conduct is right，prudent or appropriate.
Instead，the measure is an objective one — would a hypothetical sensible and rational person in his position have done the act and in the manner that it was done？ Reasonableness judges a person by what others would have done.
It should be pointed out that reasonableness may not mean doing what the majority would do.It is possible that the majority are careless.For example，on a highway where the maximum speed limit is 80 kmph，it is possible that the great majority of drivers are driving at speeds of 90 kmph and beyond.But that does not mean it is reasonable to drive at 90 kmph.Rather，the question is at what speed the hypothetical sensible and careful driver would drive.The answer，it seems，is 80 kmph，or lower.
The most prominent application of reasonableness in law is in the tort of negligence.Negligence is the failure to do what a reasonable or reasonably careful person would have done.This duty to take care applies to each person in his personal capacity as well as in his professional or business capacity.
In contract law，reasonableness is often the measure for deciding whether a clause should be upheld.For example，“non-compete” clauses （in legal terms — restraint of trade clauses），which seek to restrict an employee or the seller of a business from working in competition against the employer/buyer，are subject to this test.In a nutshell，the law says that the clause is valid only if it is reasonable in terms of duration，geographical boundary and scope of work or business activity.For example，if an employee works only in France，it may be unreasonable to restrict him，upon leaving the company，from working anywhere in the European Union （EU）.
In company law，a director is expected to exercise care，skill and diligence as he carries out his duties.In so doing，the law requires him to rise to the standard of a reasonably competent director.
In administrative law （law relating to the regulation of governmental agencies），while decisions of a public body are，in general，not subject to judicial scrutiny，a decision may be challenged on the ground of what is known as Wednesbury unreasonableness （a principle laid down by an English court in Associated Provincial Picture Houses v.Wednesbury ）.According to this principle，an administrative decision may be subject to judicial review if it is so outrageous that no sensible person could have arrived at it，such as allowing a motor racing track to be built in a residential estate.
Finally，reasonableness is often stated as a possible defence to liability，both in the criminal and civil realms.For example，it is common to find a provision in companies legislation providing that in proceedings against a director for breach of duty，the court can grant him full or partial relief if he had acted honestly and reasonably，and ought fairly to be excused （e.g.section 391 of the Singapore Companies Act）.（The astute reader will observe that all the three basic notions of justice are employed here.）
The notion of reasonableness is an important one and is often resorted to for setting norms of behaviour in society and in business.