A movement that we will to execute is never more than a represented movement, and appears in a different domain from that of the executed movement, which always takes place when the image is vivid enough.
Ernst MachEveryone is free to set up an opinion and to adduce proofs in support of it. Whether, though, a scientist shall find it worth his while to enter into serious investigations of opinions so advanced is a question which his reason and instinct alone can decide. If these things, in the end, should turn out to be true, I shall not be ashamed of being the last to believe them.
Ernst MachMathematics may be defined as the economy of counting. There is no problem in the whole of mathematics which cannot be solved by direct counting.
Ernst Mach