This, however is so only on condition that one substitutes for units of reflection the great constitutive units (either Cuvier's great functional units or Geoffroy's great units of composition), in relation to which difference is still understood in terms of judgements of analogy or in terms of variation within a universal concept In any case, so long as it is subordinated to the criteria of resemblance within perception, identity within reflection, analogy within judgement and opposition within the concept, difference is not regarded as individual difference.