Jungs sensation type represents one of the two irrational modes of perception. "Irrational" is not used in a depreciative sense here - which is what one is tempted to do in our thought-driven time. It simply means that this function does not judge things. He comes to an understanding using his senses. He relies on that which he can see, hear, touch, taste and smell. One could call him the realist among the types who is completely down to earth.
In astrology the sensation function is represented by the earth signs Taurus, Virgo and Capricorn. They are concerned with what is "real" or concrete. They "grasp" things, in the true sense of the word. The earth person picks up the stimuli of his environment and categorises them. He is practical and sober. The material and physical are his domains. This is where he is strong and has a good sense of what is practicable and appropriate.
The earth type may rely on his senses without even asking whether it "makes sense". He is less open to the dimension of meaning than his opposite, the intuitive type. An example: The two of them walk through the woods together. While the intuitive person appreciates the symbolic power of mother nature, the earth type will measure the trees, maybe considering their value for building furniture.
A person who can only see material things easily loses his connection with the whole. Asked about the meaning of life, he might just shrug his shoulders. Surrounded by things, he does not think about their meaning. Therefore, he is fascinated - positively or negatively - by people of the intuitive type. In order not to waste away mentally or spiritually, he needs to expand his view of reality by adding the dimension of meaning.