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Substance / Locke: the various simple ideas have a common substance - it is corpuscular or atomic (Boyle)
Substances / Locke: Ideas about the basics of the things of the outer world, which make this appear as something unified - I 36 substance: name of the substrate. (Complete the uniformity) - substrate: the common, which is pulled out of the recurring observations - substance: complex idea, being undetectable.
An Essay Concerning Human Understanding