The third lecture of this year’s Portsmouth Institute conference, on Newman and the Intellectual Tradition, was an overview of Cardinal John Henry Newman’s famous poem, “The Dream of Gerontius,” by Boston College Philosophy Professor Peter Kreeft, with Portsmouth Abbey Chaplin Dom Julian Stead introducing the speaker:

(The remainder of Dr. Kreeft’s speech is available in the extended entry of this post.)
The poem — and the speech — is an artistic exploration of the notion of Purgatory. Indeed, during the Q&A of Prof. Paul Griffiths’ presentation an audience member related the anecdote of having successfully used the poem to persuade a fellow Christian of Purgatory’s reality. One thread of that topic that Dr. Kreeft drew out for consideration was the existence of demons, suggesting that (in general) there are two “recipes for failure” against an opponent: denying your enemy’s existence and/or underestimating him, and overestimating him and thinking him insurmountable.
The second error set my thoughts in motion when Kreeft suggested that just the sight of demons is “real despair,” drawing a distinction between them and cinematic monsters, however visually scary they may be. It is the stench of insurmountability. The fear isn’t fright, but a feeling of ultimate hopelessness.
Here, we come again to an area in which it becomes difficult for believers and non-believers to communicate, because on spiritual matters, we inevitably use physical representations in describing immaterial things, and non-believers take their lack of tangible experience with corporeal beings as evidence that “immaterial” means “non-existent.” It’s difficult to conceive of volitive creatures not as monsters, but as abstract emotions like (say) depression. But we lose a dimension of reality, I think, a fruitful way of considering the world around us, when we systematize everything as mechanical and without intention.