It was for meditation and philosophising that Batman and his young cohort Robin would retreat to the Bat Cave. Weary from the rigors of heroic crimefighting and desirous of a period of quiet reflection and renewal, they would spend hours in the cool dank chamber, reading the works of Confucius, Plato, Aquinas, Kant, Locke, Hobbes, Aristotle, Augustine, Descartes, Pascal, James, Russell, Schopenhauer, Aurelius, Kierkegaard, Ockham, Spinoza, Hume, Hegel, Nietsche, Bergson, Whitehead, Santayana, and many other great philosophers.
When not reading, the two would discuss for hours the mysticism of the Pythagoreans, or debate far into the night the merits of pragmatism versus those of positivism.
Such was their devotion to the realms of the mind during these times of seclusion that not even the direst of criminal threats to the citizens of Gotham could tear Batman and Robin away from their books. By some mysterious sixth sense, the city's worst criminals would know when the dynamic duo were thus cloistered and would wreak their worst fraud, pillage, mayhem, and pandering, all without opposition. "There are nastier things in heaven and earth than are dreamt of in your hidey-hole, Batman" the Joker would cackle. "What is the sound of one bank robbery?" the Riddler would ask quizically.
But on balance, in the long run, who can say with certainty that the criminals came out ahead? It could be argued that during these periods of apparent neglect of their calling, the duo were in fact undergoing a process of renewal that enabled them to pursue their crimefighting activities with redoubled vigor.
Even superheroes need sabbaticals.