但是，要界定什么是勇敢，往往被证明跟在愚者中区分出智者一样的棘手。对于柏拉图和许多其他的权威来说，勇气首先是一种搏击术，最容易在战场上展示出来——标志性的铁血战士冲破火线救出受伤的战友。
But Dr. Kateb points out that if courage finds its highest expression in war, then the trait paradoxically becomes an immoral virtue, ennobling war and carnage by insisting that only in battle can men — and it usually is men — discover the depths of their nobility.
但是卡泰博士指出，如果说勇敢在战争中有最高表现的话，那么其特点就自相矛盾地成为不道德的美德，强调人们，通常是指男人，只有通过战争才能发掘其灵魂深处的高贵，从而把战争和屠杀高尚化。
Marilynne Robinson, the novelist and social critic, has observed that courage is "dependent on cultural definition" and "rarely expressed except where there is sufficient consensus to support it." Where religious martyrdom is lionized, there will be martyrs; where social or political protest is seen as glorious warfare in civvies, there will be a rash of red-faced declaimers, soapboxes on every street.
玛丽琳·罗宾逊（Marilynne Robinson），小说家和社会评论家，她已经注意到勇气"依赖于文化定义"，"很少被表达出来，除了在得到足够的舆论支持的场合"。在为宗教而罹难者被奉为圣人的地方，就会有殉道者；在社会或政治抗议被视为光荣的平民斗争的地方，每一条街道临时搭建的演讲台上就都会充斥着面红耳赤、激昂陈词的演说家。
In pioneering work from 1970s and beyond, Stanley J. Rachman of the University of British Columbia and others studied the physiology and behavior of paratroopers as they prepared for their first parachute jump.
在上世纪70年代及之后的开创性工作中，不列颠哥伦比亚大学的斯坦利.J.拉赫曼（Stanley J.Rachman）等人在其首次跳伞准备的过程中研究了伞兵的生理及行为特征。