In its application to natural science Grosseteste based his method of verification and falsification on two assumptions about the nature of reality. (a) The first was the principle of the uniformity of nature, meaning that forms are always uniform in their operations.... In support of this principle he quoted 'Aristotles II de Generat.:...'the same cause, provided it remains in the same condition, cannot produce anything but the same effect.' (b) The second assumption Grosseteste made was that of the principle of economy, or lex parsimoniae. This he also derived from Aristotle, who stated it as a pragmatic principle.