Why can community benefit if its individuals be free to act selfishly?

Question

I never studied philosophy. Can someone kindly explain like I'm 5 the emboldened sentences below? What does "the defendant may benefit from considerations such as the effect on the community if everyone were prevented from behaving as did she" mean?

AP Simester, ‘Can negligence be culpable?’, in Jeremy Horder (ed.), Oxford Essays in Jurisprudence: Fourth Series (Oxford: Oxford University Press, 2000), p 94.

Divergence

Core cases are all very well, but others lie at a distance from the paradigm so far considered. Logically, it is possible for the values of a legal system and those of general morality to conflict, even explicitly. In Toledo, &c. Railway Co v Pindar,27 for instance, the plaintiff Pindar was held contributorily negligent for saving some horses rather than a sum of money when both were threatened by fire, on the ground that the former were much less valuable than the latter and that the suffering of the horses was of no legal account. While the decision may reflect considerations specific to tort, it is hard to see how that approach could be defended in contexts where culpability provides the rationale for judgment; especially in criminal law. If the defendant’s behaviour is morally acceptable it cannot be the subject of blame and, therefore, should not be subject to criminal condemnation or punishment.
      To a large extent, the analysis offered here is content independent. It does not seek to identify which acts defendants are required (i.e. under a duty) to avoid. This is because, generally speaking, the moral constraints upon law are exculpatory not inculpatory. Let there be no judgment without blame. But there may be blame without legal judgment. My failure to rescue a stranger may be reprehensible, lawful, and properly so.28 Similarly, in the evaluation of reasonableness, not all considerations will be straightforwardly moral in character. It may be noble to prefer the interests of others yet, for reasons of convenience or self-interest, acceptable not to. Thus, in Marshall v Gotham Co Ltd,29 where measures required to minimise the risk of a mine roof falling were complex, expensive, and partial rather than comprehensive, the House of Lords ruled that the defendants were not negligent in continuing to mine without such precautions. It can be in the interests of a community that individuals be free to act selfishly; in turn, the defendant may benefit from considerations such as the effect on the community if everyone were prevented from behaving as did she.30
      On the other hand, the justified content of law may depend on values over which there is genuine disagreement. This presents no particular difficulties for the analysis of negligence. When we criticise particular rules,31 as many of us do, we implicitly argue that the reasons for which the defendant is required to act should in some way

p 95

be modified. A committed anti-vivisectionist might argue that a reasonable person should want to prevent vivisection sufficiently strongly that he would consider it acceptable to bomb an animal testing laboratory; a devoted spouse, when denying that euthanasia is immoral, impliedly contends that the desire to preserve life should not always be overriding. Others will dissent. The disagreement simply manifests how difficult it can be to concur whether an outcome is morally desirable.

Answer 1

Selfish behavior can often benefit the community. For example, most economic activities are selfish and also beneficial to the community.

You sell legal services for monetary gain; Your clients receive legal services at a drastically reduced price and/or increased quality than by producing those services for themselves.

If there is genuine disagreement about the morality of your profit seeking behavior, you could argue that the community would lack such services if everyone were prevented from charging for those services.

Answer 2

Other answers have explained generally why selfish behavior can sometimes benefit the community. I will attempt to explain the phrase "the defendant may benefit from considerations such as the effect on the community if everyone were prevented from behaving as did she."

Let us use the author's example of the mining company which had an opportunity to take certain precautions to minimize the risk of a mine roof falling. The author explains that these precautions would be complex, expensive, and partial rather than comprehensive---meaning that even if the company took these complex, expensive precautions, the risk would only be partially reduced. The author says that the company decided to continue to mine without these precautions. Somehow it came to the House of Lords to rule on whether the company was negligent for mining without these precautions, and the House of Lords ruled that it was not negligent.

behaving as did she: In this case, mining without the precautions.
if everyone were prevented: Let us imagine a hypothetical community in which everyone were prevented from mining without the precautions. In other words, mining would be possible only with these complex, expensive precautions, which only partially reduce the risk of the mine roof falling.
the effect on the community: Comparing this hypothetical community to our own, we can begin to imagine the effect on the community: Mining would become more expensive overall. Some mines might go out of business and close. Coal or other mining products would become more expensive. The question is whether these effects would harm the community, and how much.
the defendant may benefit from considerations such as: If the court thought these effects would be benign, it would not affect the case. On the other hand, if the court thought these effects would harm the community, this could be a reason to accept mining without the precautions as justifiable and rule that the company was not negligent.