Pada saat saya berpikir bahwa saya telah belajar bagaimana hidup, sebenarnya saya telah belajar cara untuk mati. - Leonardo da Vinci

Avoid studies of which the result dies with the worker.

If you take as your pattern the wings of feathered birds, these are more powerful in structure of bone and sinew because they are penetrable, that is to say the feathers are separated from one another and the air passes through them. But the bat is aided by its membrane, which binds the whole together and is not penetrated by the air.

The spirit has no voice, because where there is a voice there is a body, and where there is a body space is occupied, and this prevents the eye from seeing what is placed behind that space; hence the surrounding air is filled by the body, that is by its image.