To use the crimes of the past as a reason to block change in the world now is just laziness.
Do you know what a scientist fears most in this world above all else? It's oblivion, my friend. A scientist measures our lives in the ways we develop and expand our knowledge through myriad variations. Nothing can take its place. It's our very soul. I have done the worst thing one scientist can do to another: I have altered your thought process. When my drug takes effect, you will find your mind has lost the ability to think.
There is no such thing as perfect in this world. That may sound cliche, but it’s the truth. The average person admires perfection and seeks to obtain it. But what’s the point of achieving perfection? There is none. Nothing. Not a single thing. I spit on perfection! If something is perfect, then there is nothing left. There is no room for imagination. No place left for that person to gain additional knowledge or abilities. Do you know what that means? For scientists such as us, perfection only brings despair. It is our job to create things more wonderful than anything before them, but never to obtain perfection. A scientist must be a person who finds ecstasy while suffering from that antinomy.
I hate perfection. To be perfect is to be unable to improve any further.
[to Nemu about Uryuu. Nemu is currently attempting to restrain Uryuu so Mayruri can heal him, but she is unknowingly smothering him with her breasts] Yes, Nemu. Just smother him with those things. Worst case, he dies happy.
[to Szayel Aporro Grantz] Immaculate being... Was it? In this secular existence, perfection is an illusion, regardless of those who utter the contrary. This is the reality. Common man seeks it out, they strive to achieve it, as if it were some tangible thing... But... The fact of the matter is, perfection is a hollow shell. It is devoid of any substance. I spit on perfection. Perfection, after all, implies you've reached the summit. No trial and error, no ability to conceptualize. An omniscient being would have no need for such superfluous things... Am I making myself clear? For people who dabble in the sciences, such as ourselves, perfection would make us obsolete. Many magnificent things have been, and will continue to come into existence... And yet every last one of them will fall short of perfection's finish. Our function as men of science relies on their many shortcomings. Then, and only then, can we apply the fruits of our labor. To put it simply... As soon as you began spouting that nonsense about being an immaculate being... your fate was sealed. How dare you call yourself a man of science?
Oh, you know what I'm talking about. That stupid line that all you Quincies keep saying up until the moment you die. By the honor of the Quincy I cannot do this, by the honor of the Quincy I won't allow that. Quincy this, Quincy that! Every last one of you! It's so annoying!
Killing you now will be as easy as strangling a baby. A grenade that's thrown should not come back.