And yes, I believe that there is a great, real and rather obvious difference. For starters we can start with the amount of suffering involved. If someone is going to, with a straight face, try to convince me that the "suffering" undergone by a truckful of cabbage is anything approximating that undergone by say a truckload of pigs, well then I have very little else to say, and it would be best for at least the rules of this forum if we leave the debate just there.
Well, it seems that your criteria of suffering is a little limited and only adresses the suffering of suffering.
Raising, killing and eating an animal is just simply involving more suffering than even the worst case scenario of the amount of bugs we kill in producing a non-meat meal.
I don't think the suffering of a mammal is qualitatively or quantitatively greater than the suffering of an insect -- I know that some Buddhists make this (false) disctinction, but the monastic penalty for killing an insect is no less than that of killing a cow -- it merely requires confession. What this says to me is that Buddha valued the life of all creatures equally regardless of phyla. Destroying vegetation, especially seeds, is also included in this class of vows, as is digging in the ground.
Remember also that some of those same bugs are also killed in the process of slaughtering an animal.
Part of that precise answer would, in addition to suffering, most definitely deal with the presence or absence of a central nervous system, although if you will that could be a duplication of the suffering argument.
This is a value judgment you are making that does not have an objective base.
It is a certainly the case that in Early Buddhism the issue was not so clear cut among Buddhists. Coming from a common Vedic Heritage where plants are considered fully qualified animate beings, early Buddhists also held this view. Only later, under the influence of scholastic dogmatism, did Buddhist philosophers begin to argue plants were non-sentient. The Buddhist arguments against plant life being sentient are quite late, motivated it seems mainly to defend Buddhist from criticisms from Jains and Hindus. Lambert Schmithausen wrote a long and interesting article about this and concludes (http://www.scribd.com/doc/78950014/The- ... t-Buddhism
):But as stated above (§ 5.2 and n. 204) a few sources suggest yet another
motivation, viz. that plants should not be injured or destroyed because they are the
abode or habitat of animal s (cp. also the analogous motivation not to
pollute water in § 11.1). This ecological argument is fully valid today also,
indeed more than ever before, and for both monks and lay people.
39.2 However, I for one should find it reasonable to combine this latter
argument with a different view of the nature of plants - one that is perhaps not too
far from what I hope I have been able to show to have been, with some probability,
that of earliest Buddhism: the view that plants themselves, too, are living
beings, in the sense of a border-line case. But contrary to the situation
in earliest Buddhism where the border-line status of plants served to reduce
inhibitions against injuring them, it should now be used to re-establish them.
In this sense, we should rather stress the other aspect of the border-line status: Plants
are, to be sure, not living beings like animals, and not at all living beings like men,
with some secret anthropomorphic features and faculties, and hence perhaps not
sentient beings in the usual sense of the word; but not entirely insentient either, not
altogether insusceptible of being injured; living beings of a peculiar kind,
which we can somehow explore from outside, but which we will probably never be
able to "understand" from within; familiar beings, but at the same time utterly strange,
and precisely for that reason to be treated with respect: because we simply do
not know, and perhaps cannot even imagine, what it means for a plant itself to
be injured. To be sure, unless we are ready to starve, we cannot avoid using plants,
and this often means: injuring or even killing them. But we should do this as
little as possible, carefully and with a sense of regret, not with
the unnecessary brutality and relentlessness which has become habitual, and at the root
of which is mostly not need but greed.
This whole argument equating animal sentience with plant "sentience" is simply a last-ditch, desperate and rather unbecoming argument, designed to defend our choices as meat-eaters.
I did not equate the two. I merely pointed out that I no longer believe that anything imbued with prāṇa can possibly be non-sentient. Plants possess prāṇa, therefore, they are alive, therefore, after some fashion, I must accept that they too are sentient. Not only to plants possess prāṇa, but they also possess ojas, mdangs, they also possess the seven phase digestive process that we humans and all animals do. They take food, they break it down, is it conducted by fluid within plant membranes where it builds their flesh, their soft tissue, hard tissues and finally in the end they produce sap, flowers, seeds, etc.
I will state that, based on my understanding of Dzogchen teachings, those Buddhist scholastics who argued that plants were not alive, equivalent with rocks and crystals, were wrong in their understanding.
I accept without any reservation that a vegetarian meal involves death and suffering, but not more so, or even equal, than the death and suffering involved in eating meat.
Again, I respect everyone's choice in what they eat and do not eat, and what you eat or not will not liberate you, but let's not make stuff up to make us feel better.
When growing plants in the large quantities made necessary buy the increasing population of the our planet is made possible only through the use of animal-based fertilizers that come from the death of animals in the billions, such as in organic agriculture, or the petrochemical fertilizers/pesticides/herbicides that contaminate the environement and poisoin billions of birds and insects, such as in conventional cultivation, there is no solid argument than can be made that a vegetarian diet, even a so called organic veb is less harmful to animals than a non-vegetarian diet. It simple does not add up.
So let us not pretend that being a vegetarian is intrinsically more moral or better than being an omnivore. Vegetarians who argue in that way are simply being false brahmins.