the comic strip characters‟ speeches doubt science and its findings through the centuries by the use of conditional sentences that require the use of imperative to express the idea of moral obligation. 

the disbelief about scientifically proven truths is satirized by the use of conditional sentences, which are usually employed to represent scientific facts and general truths. 

the distrust on scientific achievements from the 15th to 21st centuries is explicit by the linguistic structure of the conditionals, expressing actions or situations that are likely to happen in the future. 

the clear incredulity about the lack of scientific evidence is presented through the use of conditionals, expressed by hypothetical situations in the past represented as centuries went by. 

the characters on the comic strip doubt the scientific findings, and the conditional structure is used to reinforce that those findings were not discovered.