ABSTRACT
Ellis’ critical remarks are not so telling against Armstrong as they are against ‘naive’ viewpoints. Ellis believes that the realist misses the essentially relational character of quantities. Temperature, pressure, density, etc., are all bona fide quantities, but none are extensive. To strengthen the Ellis theory by requiring all quantities to be extensive structures would therefore be to render it too restrictive. If the life forms were able to perform experiments on the copper tubing, they would soon detect differences in the orders associated with the quantities. The objection just considered may be termed “extensionalist” in that it states that there are different quantities with the same extension. Any account of quantities must accord with measurement as it is practised in science. Objects in an ordered class not embedded in a network of laws would not be measurable in the sense in which the objects investigated in science are measurable.
