There are those who go as far as to affirm that mortal sin, which causes separation from God, only exists in the formal refusal directly opposed to God's call, or in that selfishness which completely and deliberately closes itself to the love of neighbor. They say that it is only then that there comes into play the fundamental option, that is to say the decision which totally commits the person and which is necessary if mortal sin is to exist; by this option the person, from the depths of the personality, takes up or ratifies a fundamental attitude towards God or people. On the contrary, so-called "peripheral" actions (which, it is said, usually do not involve decisive choice), do not go so far as to change the fundamental option, the less so since they often come, as is observed, from habit. Thus such actions can weaken the fundamental option, but not to such a degree as to change it completely. Now according to these authors, a change of the fundamental option towards God less easily comes about in the field of sexual activity, where a person generally does not transgress the moral order in a fully deliberate and responsible manner but rather under the influence of passion, weakness, immaturity, sometimes even through the illusion of thus showing love for someone else. To these causes there is often added the pressure of the social environment.