Why should one not hurt or inflict pain on any animal that can experience fear?

Questioner: So how can one attain absolute Ahimsa?

Dadashri: Ahimsa? My goodness! If one attains absolute Ahimsa, he would become The Lord. In the meantime however, do you practice at least some Ahimsa?

Questioner: Some, not a lot.

Dadashri: Very well then, why don't you make a decision to practice at least some Ahimsa? It is futile to talk about achieving absolute Ahimsa. Such Ahimsa when achieved makes man The Lord.

Questioner: Show us how to practice Ahimsa.

Dadashri: Most important of all, you must not hurt or inflict pain on any living being that fears your mere presence.Animals and insects instinctively flee from you in fear, and so you must not harm them. It is fine for you to eat grains such as wheat, millet, oats, rice etc., because although they contain life, that life is in an unconscious state and does not perceive fear, whereas insects will flee from you when they sense danger. You must not harm any life forms starting at the level of two-sensory organisms such as the fish, which move around, all the way to the five-sensory organisms, including insects. Even a bedbug is terrified when you catch it, so you must not kill it. Do you understand this?

Questioner: Yes, I understand.

Reference: Book Name: Non-Violence (Page #33 - Paragraph #3 to #8; Page #34 - Paragraph #1, #2)

So, you must not interfere with the violence that occurs as a result of eating single-sensory life-forms. To do so is involves ego. The single-sensory life forms do not run away from you in fear, so you should not have any qualms about whether or not to eat them. This is the way of life. You cannot survive without eating and drinking.

The entire world is composed of life forms. Actually, the whole world is a collection of life forms. The basis of life is at least single-sensory. You cannot eat anything that does not contain life; moreover there is nothing in this world that is void of life. You can only eat food that contains life because that is the only way you can nourish and sustain your body. Everything we eat is at least one-sensory life form, if not more. The Lord does not forbid the consumption of single-sensory organisms because they do not contain blood, pus or meat.

Reference: Book Name Non-Violence (Page #35 - First Paragraph; Page #36 - Paragraph #1, #2)