It was on the 10th day of May - 1884 - that I confessed to age by mounting spectacles for the first time, and in the same hour I renewed my youth, to outward appearance, by mounting a bicycle for the first time. The spectacles stayed on.
Practice is absolutely necessary. You may sit down and listen to me by the hour every day, but if you do not practice, you will not get one step further. It all depends on practice.
Things which we see are not by themselves what we see ... It remains completely unknown to us what the objects may be by themselves and apart from the receptivity of our senses. We know nothing but our manner of perceiving them.