Others diverted their minds from faith by heading in a different direction. They claimed this sign, the exorcism, was not in itself enough to warrant faith.
It is not faith that is irrational, but unbelief. Unbelief is the twisting and turning of the mind in its refusal to submit to God and his revealed truth. We see the same thing when witnessing to people about the gospel. They bring up one objection, and we carefully try to answer the matter. They then leave that subject, being unable to successfully argue their case any further, and immediately they switch to another objection. Their minds are desperately grasping hold of anything within reach to justify their refusal to believe, and to fend off God from having any place in their lives. They do not want to believe.