By a lie a man throws away and, as it were, annihilates his dignity as a man. A man who himself does not believe what he tells another … has even les… - Immanuel Kant

By a lie a man throws away and as it were annihilates his dignity as a man

La incapacidad significa la imposibilidad de servirse de la propia inteligencia sin la guía de otro. Esta incapacidad es culpable porque su causa no reside en la falta de inteligencia sino de decisión y valor para servirse por sí mismo de ella sin la tutela de otro. ¡Sapere aude! ¡Ten el valor de servirte de tu propia tazón!: he aquí el lema de la Ilustración.

Nature does nothing in vain, and in the use of means to her goals she is not prodigal. Her giving to man reason and the freedom of the will which depends upon it is clear indication of her purpose. Man accordingly was not to be guided by instinct, not nurtured and instructed with ready-made knowledge; rather, he should bring forth everything out of his own resources.

Newton... (after having remarked that geometry only requires two of the mechanical actions which it postulates, namely, to describe a straight line and a circle) says: geometry is proud of being able to achieve so much while taking so little from extraneous sources. One might say of metaphysics, on the other hand: it stands astonished, that with so much offered it by pure mathematics it can effect so little. In the meantime, this little is something which mathematics indispensably requires in its application to natural science, which, inasmuch as it must here necessarily borrow from metaphysics, need not be ashamed to allow itself to be seen in company with the latter.