In part II of Hume's Dialogues Concerning Natural Religion Cleanthes maintains that the similarities between the works of nature and those of human contrivance, namely, the presence of means to ends relations and a coherence of parts, are sufficient to enable us to reason analogically to the conclusion that the cause of the design of the world resembles human intelligence. Philo objects to this on a number of grounds. The basis of his objections is to be found in his claim that the world does not bear a 'specific resemblance' to machines of human contrivance, i.e., there are not enough similarities between the world and machines to enable us to classify the world as a machine of a certain type, and therefore we are unable to proceed analogically to a similarity in the causes of the design of the world and machines. According to Philo, without such a specific resemblance, to establish the origin of the design of the world from intelligence requires seeing God and his product constantly conjoined (Hume's official account of how we learn what causes what); since we have never seen ‘worlds formed under our eyes’ we are unable to rule out alternative principles of design – both those whose effects we have observed on earth, and others whose influence is not found within the world itself. In short, Philo's criticisms of Cleanthes' argument show that he has misgivings about the evidence which the argument utilizes: he holds that more is needed besides the mere presence of means to ends relations and a coherence of parts before we are justified in postulating intelligence as the cause of design.