Science and philosophy have always learned from each other. Philosophy tirelessly draws from scientific discoveries fresh strength, material for broad generalisations, while to the sciences it imparts the world-view and methodological im pulses of its universal principles. Many general guiding ideas that lie at the foundation of modern science were first enunciated by the perceptive force of philosophical thought. One example is the idea of the atomic structure of things voiced by Democritus. Certain conjectures about natural selection were made in ancient times by the philosopher Lucretius and later by the French thinker Diderot. Hypothetically he anticipated what became a scientific fact two centuries later. We may also recall the Cartesian reflex and the philosopher's proposition on the conservation of motion in the universe. On the general philosophical plane Spinoza gave grounds for the universal principle of determinism. The idea of the existence of molecules as complex particles consisting of atoms was developed in the works of the French philosopher Pierre Gassendi and also Russia's Mikhail Lomonosov. Philosophy nurtured the hypothesis of the cellular structure of animal and vegetable organisms and formulated the idea of the development and universal connection of phenomena and the principle of the material unity of the world. Lenin formulated one of the fundamental ideas of contemporary natural science—the principle of the inexhaustibility of matter—upon which scientists rely as a firm methodological foundation.
The latest theories of the unity of matter, motion, space and time, the unity of the discontinuous and continuous, the principles of the conservation of matter and motion, the ideas of the infinity and inexhaustibility of matter were stated in a general form in philosophy.
Besides influencing the development of the specialised fields of knowledge, philosophy itself has been substantially enriched by progress in the concrete sciences. Every major scientific discovery is at the same time a step forward in the development of the philosophical world-view and methodology. Philosophical statements are based on sets of facts studied by the sciences and also on the system of propositions, principles, concepts and laws discovered through the generalisation of these facts. The achievements of the specialised sciences are summed up in philosophical statements. Euclidian geometry, the mechanics of Galileo and Newton, which have influenced men's minds for centuries, were great achievements of human reason which played 'a significant role in forming world-views and methodology. And what an intellectual revolution was produced by Copernicus' heliocentric system, which changed the whole conception of the structure of the universe, or by Darwin's theory of evolution, which had a profound impact on biological science in general and our whole conception of man's place in nature. Mendeleyev's brilliant system of chemical elements deepened our understanding of the structure of matter. Einstein's theory of relativity changed our notion of the relationship between matter, motion, space and time. Quantum mechanics revealed hitherto unknown world of microparticles of matter. The theory of higher nervous activity evolved by Sechenov and Pavlov deepened our understanding of the material foundations of mental activity, of consciousness. Cybernetics revealed new horizons for an understanding of the phenomena of information interactions, the principles of control in living systems, in technological devices and in society, and also the principles of feedback, the man-machine system, and so on. And what philosophically significant pictures have been presented to us by genetics, which deepened our understanding of the relationship between the biological and the social in man, a relationship that has revealed the subtle mechanisms of heredity.
The creation and development by Marx, Engels and Lenin of the science of the laws of development of human society, which has changed people's view of their place in the natural and social vortex of events, holds a special place in this constellation of achievements of human reason.
If we trace the whole history of natural and social science, we cannot fail to notice that scientists in their specific researches, in constructing hypotheses and theories have constantly applied, sometimes unconsciously, world-views and methodological principles, categories and logical systems evolved by philosophers and absorbed by scientists in the process of their training and self-education. All scientists who think in terms of theory constantly speak of this with a deep feeling of gratitude both in their works and at regional and international conferences and congresses.
So the connection between philosophy and science is mutual and characterised by their ever deepening interaction.