Watching Alien, I became increasingly frustrated with the cat, Jonesy, that seem to be a big distraction to the characters and even sometimes lead to their demise. The first time we encounter the cat, Brett must chase after it in order for it to not interfere with the motion detecting apparatus. However, as the plot continues, the quest for Jonesy seems more and more counterproductive. I began wondering what was the point of the cat and what place did it have in a story that included spaceships, distant planets, robots and of course an alien. Upon further reflection, I have realized that the cat serves as a foil to the alien.
The alien and the cat represent two distinctly different ideas of what a non-human being can be. Jonesy is everything that the alien is not. Jonesy, or cats in general, is domesticable and (though I personally hate cats) he is loveable. Cats are also generally vulnerable to their environments as opposed to the alien that is vicious and adaptable. I think the cat also represents something normal for the crew of characters in the movie. While battling an altogether foreign creature, the cat reminds them of the promise of home and an ordinary existence. Though the quest for finding and saving Jonesy may seem unrealistic from and outside point of view, I can understand why he was so important to the characters.