Coming-of-age (Metaphor)
Kant compares the process of enlightenment to the process of coming of age. A person without the ability to think independently is like a child incapable of walking on their own. Guardians keep mankind in a state of prolonged infancy. The metaphor of coming-of-age suggests that being autonomous requires taking responsibility. Infants take no ownership, control, or responsibility over their lives, as everything they do is managed by another. But when the child comes of age, they must decide how to think and what to do, thus taking responsibility for themselves. This suggests that the capacity for enlightenment is intrinsic to human nature, which involves both autonomy and the ability to take responsibility. Enlightenment is a matter of embracing this capability.
Shell and kernel (Metaphor)
Kant uses the metaphor of a seed encased in a hard shell to depict the relationship between civic freedom and intellectual freedom. He writes:
“A lesser degree of civic freedom, however, creates room to let that free spirit expand to the limits of its capacity. Nature, then, has carefully cultivated the seed within the hard core—namely the urge for and the vocation of free thought. And this free thought gradually reacts back on the modes of thought of the people, and men become more and more capable of acting in freedom. At last free thought acts even on the fundamentals of government and the state finds it agreeable to treat man, who is now more than a machine, in accord with his dignity.”
In Kant’s metaphor, the sturdy shell acts as a protector, providing a safe environment for the seed to develop. The growing of the seed is the process of gaining enlightenment, and the space the shell provides represents intellectual freedom. For Kant, a limitation on civic freedom does not inhibit the activity of free thinking, but rather, provides the space within which it can develop. Eventually, free thinking will influence political structures, and human beings, like fully grown plants, will flourish.
