The case of "killing" plants vs killing animals; It's the Sentience...I "feel"

Ever since I have started carpooling with a friend, we end up discussing a lot of issues, some of which we may not really concur on. One of this is the idea of killing animals for the purpose of food. Before non-vegetarian readers rally against me, let me make it clear that some of my best friends are non-vegetarians. Consumption of meat is not an issue on which I target individuals but one where I try to understand people's motivations (or the lack of it to change their lifestyle).

The conversation started by a question I posed by speaking out aloud "I wonder if it is possible for us to not be able to relate to the pain of an animal that we slaughter (not necessarily by our own hands) for food". In case you are wondering, I do not use parentheses when I speak - that is just meant to preclude any thoughts that may run off in tangents.

My friend, in the spirit of a good discussion for the next 30 mins, indulged me and joined issue. A lot of points were discussed and it ultimately rested on a piece that often comes up in the discussion between vegetarians and non-vegetarians - "Plants too are living beings and by hurting them one really is not practicing the tenet of not hurting beings". I tried to draw a line between taking the life of an animal like a sheep or plucking a tomato (or cutting a tomato for a salad). However, I was not able to articulate it properly because I do not think I knew a lot in this field.

I accepted my lack of an adequate response to this point but came home and searched for information on the internet. Like all things that you search for, this question too was discussed umpteen number of times across different fora. The main point that differentiates plants & animals is the capability of sentience in the latter which is missing in the former.

What is sentience? Wikipedia introduces it as

the ability to feel, perceive, or to experience subjectivity....In modern Western philosophy, sentience is the ability to experience sensations (known in philosophy of mind as "qualia"). The concept is central to the philosophy of animal rights, because sentience is necessary for the ability to suffer, which is held to entail certain rights.

And that, my friend, differentiates "killing" a plant from killing an animal. An animal, individually as well as as a species, has preferences, tastes, feels happiness, sorrow, anger among other things. Plants do not exhibit these characteristics. So, while plants are beings in the sense that they grow, employ processes like transpiration and photosynthesis, they do not have feelings towards another plant of the same variety or another variety. And that is why the argument that eating plants or their products is also an act of killing life is not tenable.

PS: While having this discussion or many discussions, I noticed that most of the times discussions involving laymen like most of us, concentrate more on comparing a stand with other similar ones instead of evolving a stand objectively e.g. many times people have tried to show me how I may still be hurting animals while discussing the concept of consuming meat - not necessarily with the intention of helping me improve on those counts but most probably with the intention of nullifying the steps that I am already taking in that direction. In fact, this is a style is followed in most discussions that center around one's principles.