Catherine is thinking with Nelly about marrying Edgar Linton when she doesn't love him with all her heart and soul. To be more precise, she describes her soul as the same as Heathcliff's: “'It would degrade me to marry Heathcliff now; so he will never know that I love him; and this is not because he is handsome, Nelly, but because he is more myself than I am. Whatever our souls are made of, his and mine are the same, and Linton's is as different as a moonbeam from lightning, or frost from fire'” (63). Now, not only does she love Heathcliff with all her heart and soul, but she claims that they share the same soul and that "he is more myself than I am." However, currently, Heathcliff is heartbroken because he heard her say that marrying him would be a degrading matter for her and he ran away before knowing that she loves him. Realizing that she may have heard her, but unaware of what exactly she heard, Catherine makes a conscious decision to place a barrier in the middle by marrying Linton in hopes of using his light to help Heathcliff. In other words, he is sacrificing the happiness of being with the person he loves for the chance to help her