A full appreciation for Ernst Mach's doctrine of the economy of thought must take account of his direct realism about particulars (elements) and his anti-realism about space-time laws as economical constructions. After a review of thought economy, its critics and some contemporary forms, the paper turns to the philosophical roots of Mach's doctrine. Mach claimed that the simplest, most parsimonious theories economized memory and effort by using abstract concepts and laws instead of attending to the details of each individual event (...) or experiment. For Mach, the individual case never truly repeated in all of its uniqueness, nor was all of the individual detail of a physical element adequately captured in abstract laws and schemata, however necessary these were for the pursuit of science. As can be shown from specific passages, some already published, some not, Mach's elements included physical qualia in nature similar to Russell's unsensed sensibilia, which existed even where there were no conscious observers. An argument will be presented to make the case that Mach believed in the mind-independent elements from the 1870s on, while other aspects of his thought evolved over time; I have thus dated the references to reflect this historical progression. I concentrate on Mach's ontology, as it bears on economy of thought, not his epistemology per se, which might well have been restricted to observable elements/sensations. After his own conversion to neutral monism, in the 1920s, Bertrand Russell echoed Mach's call for a 'future science' capable of handling the 'intrinsic character' of qualitative data directly without the excessive abstraction of physics. (shrink)