The more we get out of the world the less we leave, and in the long run we shall have to pay our debts at a time that may be very inconvenient for our own survival.

Phil. Leo had educated Norbert at home until 1903 employing teaching methods of his own invention except for a brief interlude when Norbert was 7 years of age. The Wiener–Khinchin theorem (or Wiener – Khintchine theorem or Khinchin – Kolmogorov theorem) states that the power spectral density of a wide-sense-stationary random process is the Fourier transform of the corresponding autocorrelation function.

A famous child prodigy Wiener later became an early researcher in stochastic and noise processes contributing work relevant to electronic engineering electronic communication and control systems. Norbert Wiener (November 26 1894 – March 18 1964) was an American mathematician. He was Professor of Mathematics at MIT.