这个话题属于典型的雅思议论文的argumentation类型。我们可以从正方和反方(for and against)两方面来阐述，也可以侧重某一方面。核心词汇包括：fixed punishments, circumstances, motivation.
The flexibility of enforcing laws has fallen into contentious topics of discussion especially when criminals are thought to do evils for some good motivations. Naturally people’s views differ from that the circumstance under which people have wrong doings should be taken into account to that fixed laws see no tolerance for any kind of crimes.
It is a bit understandable that the preference that judges are supposed to make room for the circumstance of a crime and its intentions prior to making sentence prevails among a certain number of people due to the fact that people in some extreme circumstances such as drought, flooding or even self-defense commit crimes just to survive. However, human beings’ natures pitifully make it impossible that more freedom is left to judges to decide on the punishment because human beings are born emotional and always selfish. As a result, without the prerequisite of establishment of justice and equity, the day when sentence is made in a flexible way will never arrive.
I think that it is the arbitrary law system, to be exact, the fixed punishments that do work in many aspects. For one thing, it can serve the deferring purpose and especially fills an indispensable role in avoiding the resistance or even riots in public. To a larger extent, it is able to frighten or scarce off the would-be criminals to ensure a safe living environment for the law-abiding citizens and warn those wrong doers of thinking twice. For another, this practice is surely a great consolation to the victims, for quite a few of them firmly hold that their loss of property or beloved must be compensated by merciless punishments based on fixed laws.
All in all, to ensure that the society can run smoothly before relatively perfect establishment of equity and justice, an overwhelming majority of cases have to be decided by cool laws.