The argument that the world (meaning the entire universe) sufficiently resembles a machine or a work of art or architecture, for it to be reasonable for us to posit a designer whose intellect is responsible for its order and complexity. The argument is avowedly an argument by analogy, claiming that since the universe and (say) a clock resemble each other in some respects, they probably resemble each other in the further respect of being the product of design. The argument was used by the Stoics, and had immense appeal in the 18th century, but it was overwhelmingly attacked by Hume in the Dialogues Concerning Natural Religion, and by Kant in the Critique of Pure Reason. The argument clearly invites a vicious regress, since the universe plus a designer seems an even more wonderful example of organization, and ought to lead us to postulate a designer-of-designers. If it is felt natural that a designer can ‘just exist’ (see perseity) then it has to be asked why the cosmos cannot also ‘just exist’. The argument to design also runs into moral trouble; since the nature of the deity is evidenced by his or her creation, we should not attribute more concern for goodness or justice to him or her than we find in the normal running of things (see also evil, problem of). The theory of evolution by natural selection has further undermined the effect of one of the main examples of design in nature that was often adduced, namely the adaptation of the organs and faculties of animals to their environments. However, physicists and cosmologists, impressed by the ‘fine-tuning’ of the forces that apparently govern the universe, are still prone to imagine that recourse to a guiding intelligence affords some explanation. See also intelligent design.