"I would like to emphasize at the opening of this symposium that the often quoted ratio M/L is in fact the ratio V2r/L of the directly observable quantities V, r, and L. This ratio V2r/L can only be interpreted as an indicator of mass to light ratio if we assume that Newton's law of gravitational attraction is correct on the scale of galaxies. Since Keplerian behavior is essentially never seen in extra-galactic systems, I might be so bold as to suggest that the validity of Newton's law should be seriously questioned. I hope that the observers who have definite evidence that Keplerian behavior has been observed in any system will emphasize that evidence at this meeting."