Logic
"Allowing an animal into our home is illogical," stated Sarek gravely. "Wild creatures would create undue mess, be the source for disease and allergens, and require a great deal of time and upkeep."
Amanda merely raised an eyebrow at her husband, knowing that he was not yet finished disagreeing with her.
"Furthermore, a 'pet' is not an acceptable social outlet or replacement for our son's involvement with his peer group."
"The pet I am suggesting is hardly a wild beast, Sarek. It is a well-bred Terran feline that is already house trained and has received an exemplary bill of health. Neither you nor Spock test as allergic to this species, as you well know. It will indeed require upkeep, however it will prove to be an excellent avenue for instruction in responsibility and respect for the needs of other creatures."
Sarek opened his mouth to respond to her assertions but Amanda raised one finger into the air to announce her intention to finish her comments uninterrupted.
"Furthermore, a pet will not replace Spock's involvement with other children his age, however it will help to provide the nonjudgmental companionship that a child his age needs. You know very well how challenging it has been for our half-Vulcan son to interact with his peers at times. He needs to have his human needs met from time to time as well."
Amanda grinned slightly as she observed her husband considering her statements, mulling them over in that logical mind of his.
"I have noted that over the course of our marriage you have become increasingly skilled at presenting your arguments in a logical and concise manner, thereby increasing your chances of emerging the victor in our debates."
Though his facial expression was subtle – only a minute shifting of muscle and quirk of lips – Amanda could tell that her husband could not decide between admiration for her resourcefulness or irritation at her 'management' of him.
Amanda's smile widened. "It was the logical thing to do."