Introduction:
The peddler in the story "The Rattrap" by Selma Lagerlöf believed that the world was a rattrap. He formed this belief due to his experiences and observations in life. The concept of a rattrap symbolizes the traps and snares that life sets for individuals, tempting them into undesirable situations.

Reason 1: The Peddler's Struggles
The peddler's life was filled with hardships and struggles. He was poor, homeless, and had to wander from place to place to earn a meager living. His life was akin to being trapped in a rattrap, where he was constantly trying to escape the difficulties that life threw at him. The peddler's circumstances mirrored the predicament of a rat caught in a trap, struggling to find a way out.

Reason 2: The World's Temptations
In the story, the peddler encounters a vast array of temptations and traps. He is enticed by the prospect of material gain, which mirrors the bait in a rattrap. The world presents numerous lures in the form of money, possessions, and easy gratification. These temptations are like the cheese left in a rattrap to attract unsuspecting prey. The peddler falls into the traps set by worldly desires, just as a rat would fall for the bait in a rattrap.

Reason 3: The Peddler's Isolation
The peddler is a loner and feels alienated from society. He is disconnected from human interaction and lacks a sense of belonging. This isolation is similar to being trapped in a rattrap, where one is confined and cut off from the outside world. The peddler's loneliness reinforces his belief that the world is a rattrap, as he feels trapped in his own solitude.

Reason 4: The Peddler's Transformation
However, as the story progresses, the peddler's perspective begins to change. He experiences kindness and compassion from the ironmaster, who treats him with respect and generosity. This unexpected act of kindness acts as a key to unlock the peddler's pessimistic view of the world. He realizes that not everyone is out to deceive or exploit him, and that there is goodness to be found.

Conclusion:
Initially, the peddler believed that the world was a rattrap due to his struggles, the temptations he faced, his isolation, and the traps he fell into. However, through the ironmaster's compassion, he begins to see a different side of the world. The peddler's transformation highlights the possibility of finding kindness and redemption, proving that the world is not solely a rattrap but a place where acts of goodness can prevail.