Lecture I

And then we arrive at the following: This physical human being that we confront in our ordinary consciousness is built up out of the matter which we take out of the Earth which is round about us. We continually discard this matter, and take in fresh matter, and we can definitely say that all the material substances which have been discarded by our body are replaced by new substances within periods of time of from seven to eight years. The material in us is something that is in constant flux. And so, learning to know our own life through our intensified thinking, we come to know that which remains—which endures throughout the whole of our earth-life. It is, at the same time, that which builds up our organism out of outer material substance; and this latter is itself at the same time that which we survey as the tableau of our life.