I have often wondered what justification might be used, for a philosopher to take the Tarot seriously. I suppose it depends on what kind of philosopher one is: If a logical positivist or empiricist not believing in unconscious forces of connectivity and receptivity, one could not take seriously the Tarot as means to divination or guidance.
Certainly, prominent and respected scholars have taken it seriously. CG Jung believed in using both the I Ching and the Tarot for guidance, and his acausality theory of synchronicity was his own personal rationale; I think a formidable and serious one. Synchronicity, he explained, was the process whereby the psyche could draw meaningful depictions to itself - in events, words, pictures - which would reflect the basic conflict which needed to be processed. Jung viewed the tarot pictures as representations of the archetypes within the universe, and contained in the human psyche. Lou Marinoff, one of the most prominent American philosophers and involved in the philosophical practicioners movement, uses I Ching divination with his clients. He also believes that the I Ching is simply a mirror for the contents of repressed psychic material.
The famous occult philosopher, PD Ouspensky, wrote a text called, "Philosophy of Occultism in Pictures and Numbers", in which he set forth a long and scholarly treatise concerning Kabalistic philosophy, the principles of the universe, and the manner in which the Tarot deck can help the student to become acquainted with these. In British author Anthony Peake's binary mind theory, the mechanism of divination is explained in a quite philosophic manner; drawing on quantum physics, neuro and cognitive psychology , and brain science, he describes the human mind as being a dualism. The daily self is the Eidolon, the transcendent self is the Daemon ( these are classical Greek terms). The Daemon is eternal in the Nietzschean sense, of the eternal recurrence of consciousness. Thus, if we tap into this secret self, we are highly likely to have meaningful divination experiences.
The Platonic realms of Ideas and Forms and the Kantian transcendent and universal domain, as well as the Hegelian apex of historical movement, all testify to a dualism which allows philosophy to partake in the idea of binary mind, without losing respect for empirical science.
In short, a belief in Tarot guidance is not in conflict with being a reasonable thinker; nor does it preclude one's being a serious philosopher. It is merely a question of the belief in occult forces, which is to say plainly, hidden forces, which science and psychology have proven.