Short thought on Parshas V’Eira: The medrash says that Paroh’s reaction to the first two makos was one of derision, as his magicians were able to replicate the makoh. Only by kinnim did he discover that they were unable to replicate the makoh.
The question is, why not start with kinnim? Why bother with the other two?
The answer lies in human phsychology. Had Paroh been exposed to makas kinnim initially, he would have been unable to deride the makos. Once he already derided the original makkos, even the discovery of kinnim did not cause him to change his position.
Many people today pride themselves on being “rationalists”; people who only beleive what they see with their eyes. Once such a person has staked out their position,even when confronted with evidence that runs contrary to their position, they will develop outlandish theories, and be impervious to common sense, since their initial position has already been formed.