If error is corrected whenever it is recognized as such, the path of error is the path of truth.
Hans ReichenbachOccasionally one speaks... of signals or signal chains. It should be noted that the word signal means the transmission of signs and hence concerns the very principle of causal order.
Hans ReichenbachVisual forms are not perceived differently from colors or brightness. They are sense qualities, and the visual character of geometry consists in these sense qualities.
Hans Reichenbach