[H]ere we come to the nub of the issue: the alleged moral force of the term "natural". If any creature, by its very nature, causes terrible suffering… - David Pearce

What right have humans to impose our values on members of another race or species? The charge is seductive but misplaced. There is no anthropomorphism here, no imposition of human values on alien minds. Human and nonhuman animals are alike in an ethically critical respect. The pleasure-pain axis is universal to sentient life. No sentient being wants to be harmed – to be asphyxiated, dismembered, or eaten alive. The wishes of a terrified toddler or a fleeing zebra to flourish unmolested are not open to doubt even in the absence of the verbal capacity to say so.

It's easy to convince oneself that things can't really be that terrible, that the horror I allude to is being overblown, that what is going on elsewhere in space-time is somehow less real than the here-and-now, or that the good in the world somehow offsets the bad. Yet however vividly one thinks one can imagine what agony, torture or suicidal despair must be like, the reality is inconceivably worse. The force of "inconceivably" is itself largely inconceivable here. Blurry images of Orwell's "Room 101" can barely even hint at what I'm talking about. Even if one's ancestral namesakes [aka "younger self"] underwent great pain, then the state-dependence of memories means that much of pain's sheer dreadfulness is semantically, cognitively and emotionally inaccessible in the here-and-now. So this manifesto's rhapsodies on the incredible joys that do indeed lie ahead tend to belie its underlying seriousness of purpose. For the biological strategy is propounded here in deadly moral earnest.

Humans already massively intervene in Nature, whether through habitat destruction, captive breeding programs for big cats, "rewilding", etc. So the question is not whether humans should "interfere", but rather what ethical principles should govern our interventions.