Alan's argument with Mara over emotions. While each differing view has their strong points, Alan get's the last word in the end in regards to David's developing emotions.
Dr. Alan Chaffee: That's a cruel sport.
Mara Chaffee: Life is cruelty. We all feed on each other, exploit each other in some way to survive.
Dr. Alan Chaffee: I don't agree with you. I think that adaptation is the key to survival. Cooperation and symbiosis...and compassion.
Mara Chaffee: Why do you think your own survival depends upon emotion from us? Shoul we pity you? Empathize with your plight?
Dr. Alan Chaffee: You should feel! You should feel something! Without feelings, you're nothing. You're just second-rate mimics of a higher organism. That's right, higher organisms. We're your superiors in our capacity to love. Without compassion you're a doomed species.