The thesis that scientific terms are all, or for a great part, theory-laden is quite generally accepted today. In recent years, this thesis has prompted a profound revision of the classical, positivistic philosophy of science which construed scientific laws and theories as founded on the solid, immutable rock of sense data existing "out there," independently of the observer and of his theoretical conceptions. The new, non-(or anti-) positivistic outlook brought to the fore the interdependence of theory and observation. Numerous studies worked out the implications of this new stance for the history, the sociology, and the philosophy of science.