Hi wasoxigen, thank you for jumping in with an open mind.

I suspect that many in your audience think you have sentimental reasons for believing what you do.

Don't we all feel emotional about death, particularly of the death of those humans or pets we've become attached to? I've just expanded my circle of compassion to include those that I happened to not meet, like the original post tries to explain. I fail to understand what's the problem about being sentimental about unnecessary unjust cruelty. That's what we're discussing here. All the unnecessary suffering that we chose to contribute to because of our trained, selective discrimination against certain species.

But if the emotional appeal doesn't work for you, there are plenty of scientific reasons to stop using animal products. The main ones being how much animal production contributes to depletion of resources, pollution and climate change. I won't even mention the health benefits.

The fly vs. dolphin question seems like a good one to clarify values.

I disagree. This is an ultra hypothetical question that diverts from the elephant in the room. How much I value I put on the life or a fly means absolutely nothing while we have billions of animals being raped, kept in cages without ever seeing sunshine, living short and miserable lives to eventually being slaughtered for human pleasure. Why do we do this, is the real question we should be asking.

If I had the power to eradicate all flies, I would consider it.

That could potentially have very negative effects on the birds, reptiles and other animals that eat flies for survival.

I will point out that I am a human, and more concerned with human welfare than the welfare of other creatures.

Yes, this is the species bias we're taught growing up as the original post points out.

...and partly a belief that humans are capable of suffering more acutely than many other living things.

Where do you get this belief from? Have you tried pinching a cat or dog, do animals not react to pain the same way as humans do?

What values inform your position? [...] By the time you learned to read, you had certainly annihilated vast numbers of microorganisms.

Again, we keep going back to the point of necessity and wilfulness. The question is whether we consciously chose to kill or not.

The plants and bugs in your organic garden are engaged in a vicious, thoughtless war for survival, with violence and chemical warfare regular features of their ordinary existence.

Absolutely, and the keyword here is survival. Do we humans in wealthy developed countries do it for survival or pleasure?

You recognize that we humans are special, in that we are capable of making informed choices about how we interact with our environment and affect other forms of life.

This in an incredibly biased anthropocentric view. We measure our own greatness by our own criteria. Who's to say that, for example, whales don't think the same of themselves and feel we're an abhorrent violent species with no respect for life and the planet?

Yet the "web of life" diagram is a random jumble of living things, with no acknowledgement that single-celled organisms are incapable of suffering, or that humans have no natural predators.

That's true, the diagram is of course very simplified. It illustrates two distinct ways of thinking and not meant to be a scientific drawing.

If "every living thing is valuable," how do you decide what to eat out of necessity? What is the value you wish to maximize?

That's a very good philosophical question but again distracting from the elephant in the room. Complexity, ability to suffer and social development are some of the things that come to mind on the spot. A plant can't be compared with a screaming pig for example. I don't need to explain to you the differences between them.

A simple exercise I suggest is to put yourself in the body of others and imagine how you'd feel to live the lives they endure. Then ask yourself, do I need this to sustain me or am I taking this life for personal indulgence? If you answer honestly, and take the victim's point of view into consideration (like the original post points out) you'll find your value.

In essence, do to others like you'd like done to you, is not that new or radical idea.