THOSE ARE SUBSTANCES

Although chemistry is said to be the science of substances, a clear de finition of the notion of substance is still missing. First the author criticizes some propositions that seem to be too narrow. Afterwards h e develops his own concept. Using the phenomenological method Soentgen gives a descriptive definition (definitio descriptiva). His notion of substance can be summed up by five sentences: Substances can be porti oned out. Substances are material. Substances have inclinations. Subst ances occur. Substances are natural kinds. With regard to some histori cal and present lines of discussion Soentgen emphasizes the methodolog ical relevance of his approach.