What about plants?
Plants are alive but they do not possess a central nervous system, therefore picking an apple from a tree does not have the same moral implications as confining, torturing and finally slitting a sentient animal's throat.
The truth is that plants, when stressed, release a chemical called ethylene. This chemical indicates that the plant needs to increase cell growth or take other measures against the perceived stressor.
Scientists measured levels of ethylene released from stressed plants by “listening” to them using lasers until a certain frequency was measured. While this research shows that plants might have a stress-avoidance response, it is quite a stretch to refer to this as "pain". It is even more erroneous to equate this response with the pain suffered by animals and human beings. Plants lack nerve endings, brains, hormones, and other structures that would allow them to experience pain.
Even if someone was concerned that plants were being "killed" and exploited in the same way as animals then by eating meat they would be causing harm twice because the animals they eat would have already eaten plants before being slaughtered (for example, it takes several pounds of plants to produce just one pound of beef).
Eating a vegan (plant-based) diet is not about a quest for personal purity, veganism is a way of living which seeks to exclude all forms of exploitation and cruelty to the animal kingdom, as far as is possible. We KNOW with great certainty that the farmed animals we exploit for food experience intense pain and suffering. This should be motivation enough to treat other beings that we know have the capacity to suffer with as much compassion and consideration as we can.
Furthermore the difference is that in general we cannot live without using plants; we can, however, live perfectly well without causing deliberate suffering (and death) to billions of animals.
Robert Grillo
