FORTITUDE presupposes vulnerability; without vulnerability there is no possibility of fortitude. An angel cannot be brave, because he is not vulnerable. To be brave actually means to be able to suffer injury. Because man is by nature vulnerable, he can be brave. By injury we understand every assault upon our natural inviolability, every violation of our inner peace; everything that happens to us or is done with us against our will; thus everything in any way negative, everything painful and harmful, everything frightening and oppressive.
The ultimate injury, the deepest injury, is death. And even those injuries which are not fatal are prefigurations of death; this extreme violation, this final negation, is reflected and effective in every lesser injury. Thus, all fortitude has reference to death. All fortitude stands in the presence of death. Fortitude is basically readiness to die or, more accurately, readiness to fall, to die, in battle.
Every injury to the natural being is fatal in its intention. Thus every courageous action has as its deepest root the readiness to die, even though, viewed from without, it may appear entirely free from any thought of death. Fortitude that does not reach down into the depths of the willingness to die is spoiled at its root and devoid of effective power. Readiness proves itself in taking a risk, and the culminating point of fortitude is the witness of blood. The essential and the highest achievement of fortitude is martyrdom, and readiness for martyrdom is the essential root of all Christian fortitude. Without this readiness there is no Christian fortitude. An age that has obliterated from its world view the notion and the actual possibility of martyrdom must necessarily debase fortitude to the level of a swaggering gesture.
One must not overlook, however, that this obliteration can be effected in various ways. Next to the timid opinion of the philistine that truth and goodness “prevail of themselves,” without demanding any personal commitment, there is the equally pernicious easy enthusiasm which never wearies of proclaiming its “joyful readiness for martyrdom.” In both cases, the witness of blood is equally bereft of reality. . . .In the face of the unromantic, harsh reality expressed in these grave statements, all bombastic enthusiasm and oversimplification vanish into thin air. In this, then, does the actual significance of the unyielding fact that the Church counts readiness to shed one’s blood among the foundations of Christian life become clearly manifest. The suffering of injury is only a partial and foreground aspect of fortitude. The brave man suffers injury not for its own sake, but rather as a means to preserve or to acquire a deeper, more essential intactness. . . .
The Christian loves his life, says Thomas, not only with the natural, life-asserting forces of the body, but with the moral forces of the spiritual soul as well. Nor is this said by way of apology. Man loves his natural life not because he is “a mere man”; he loves it because and to the extent that he is a good man. The same applies not only to life itself, but to everything included in the range of natural intactness: joy, health, success, happiness. All these things are genuine goods, which the Christian does not toss aside and esteem but lightly—unless, indeed, to preserve higher goods, the loss of which would injure more deeply the inmost core of human existence.