资料题：What does "ignite" mean in paragraph two（　）。

Some say that nothing is more vivid or memorable than a picture.We disagree.No visual image is as vivid as the image created by the mind in response to words.The main function of the painter or the artist, in fact, is to enable people to see more deeply into things than they can with the unaided eye.There is more to life than meets the eye, and this is what good prose or poetry or painting is all about.It is not true that one picture is worth a thousand wands.It takes only a few words-if they are the right words--to ignite the imagination and produce pictures far more colorful than anything within the range of electronic communications.Yet the ultimate importance and power of print is represented not by it superior images but by its ability to convey abstract ideas.No matter how intensive or prolonged a person's formal schooling may be, he is only partially educated if he is unable to think abstractly.He knows that the most vital ingredient(因素)in the making of decisions is sequential thought.This is what is meant by abstract thought.No other medium of communications can equal the speed and accuracy of print in moving an abstraction from one human brain to another.If we are looking for a way to kill philosophy, then let us by all means put an end to print, for print is the natural habitat of ideas.There is also a connection between reading and owning that is not accidental or incidental.People who are impressed with ideas want to think about them on their own terms and in their own time.