As for insects and arachnids, it has to do with their brain and nerve cell makeup. I cannot (cannot cannot) wrap my brain around the fact that they don't feel pain the way we do (it's all reflexive, nothing more), since they don't have the nerve cells needed in order to do so.
I haven't found a dry, awful study to cite, but there's an expert Q&A site that answers the question in the way I had it explained to me:
http://en.allexperts.com/q/Entomology-Study-Bugs-665/insects-feel-pain.htm
There have been studies with bees that measure aggression, as well - and have made for some interesting questions regarding how we define "emotion" in non-humans. Not big on citing Wikipedia, but here you go:
http://en.wikipedia.org/wiki/Emotion_in_animals#Honeybees
The link between pain and emotional response is an interesting, and extremely confusing (for this non-entomologist) one, but people far more learned in the field have concluded that spiders and insects do not feel emotion or pain in the way we do, unless you want to conclude that any reflexive negative action constitutes and emotional/pain response (which isn't their definition of it).
And SC, it looks like you might need a new jacket for yourself.
This is why many find many 'scientists' to be 'cold' and 'heartless', because they split up and try to categorize emotions in to 'different types' and 'rationalize and apply logic to it', this is not a "bad" thing but in the past scientists have used the differences between us and other species to justify their experiments, yes emotions can be some what explained by physical things and logic, but this is not always the case and like so many machines have said in movies "Emotions are not logical." this is true in some sense and emotions can also be "logical" this is also true in some sense, emotions are some what "both" and some where "in-between".~
Regardless of how 'well' some scientist thinks they know how 'pain' and 'emotional responses' work for what ever particular species, this does not cancel out the fact that we truly do not know any thing for sure yet about any species outside out own.~
And just because a creature
might experience 'pain' or 'emotions' differently than our species does
not make them nor the way that they 'feel' nor 'respond' any "less" nor "inferior" nor "not worthy of noticing".~
Have you ever heard of the horrible experiments done to animals in the past because some scientist had determined that "non-Human animals are more 'mechanical' than us, they do not truly feel pain, their responses are simply pre-programmed responses based on upon reaction" yet the writhing in apparent agony of many creatures that he dissected
while they were still alive would seem to have indicated otherwise?~
His experiments were later banned.~
Speciesism
Origin of the term
Further information: Animals, Men and Morals (link:
http://en.wikipedia.org/wiki/Animals,_Men_and_Morals ) and Oxford Group (animal rights) (link:
http://en.wikipedia.org/wiki/Oxford_Group_(animal_rights) )
Richard D. Ryder coined the term "speciesism" in 1970.
The concept of speciesism is an old one. Paul Waldau writes that the overriding of nonhuman animals' interests was traditionally justified by arguing that they existed for human use; Aristotle, for example, made this claim in the 4th century BCE, as did Cicero in the 1st century CE.[6] The term speciesism, and the argument that it is simply a prejudice, first appeared in 1970 in a privately printed pamphlet written by British psychologist Richard D. Ryder. Ryder was a member of a group of intellectuals in Oxford, England, the nascent animal rights community, now known as the Oxford Group. One of the group's activities was distributing pamphlets about areas of concern; the pamphlet entitled "Speciesism" was written to protest against animal experimentation.[7]
Ryder argued in the pamphlet that: "Since Darwin, scientists have agreed that there is no 'magical' essential difference between humans and other animals, biologically-speaking. Why then do we make an almost total distinction morally? If all organisms are on one physical continuum, then we should also be on the same moral continuum." He wrote that, at that time in the UK, 5,000,000 animals were being used each year in experiments, and that attempting to gain benefits for our own species through the mistreatment of others was "just 'speciesism' and as such it is a selfish emotional argument rather than a reasoned one."[8] Ryder used the term again in an essay, "Experiments on Animals," in Animals, Men and Morals (1971), a collection of essays on animal rights edited by philosophy graduate students Stanley and Roslind Godlovitch, and John Harris, who were also members of the Oxford Group. Ryder wrote:
In as much as both "race" and "species" are vague terms used in the classification of living creatures according, largely, to physical appearance, an analogy can be made between them. Discrimination on grounds of race, although most universally condoned two centuries ago, is now widely condemned. Similarly, it may come to pass that enlightened minds may one day abhor "speciesism" as much as they now detest "racism." The illogicality in both forms of prejudice is of an identical sort. If it is accepted as morally wrong to deliberately inflict suffering upon innocent human creatures, then it is only logical to also regard it as wrong to inflict suffering on innocent individuals of other species. ... The time has come to act upon this logic.[9]
"
Spread of the idea
Peter Singer popularized the idea in Animal Liberation (1975).
The term was popularized by the Australian philosopher Peter Singer in his book, Animal Liberation (1975). Singer had known Ryder from his own time as a graduate philosophy student at Oxford.[10] He credited Ryder with having coined the term and used it in the title of his book's fifth chapter: "Man's Dominion ... a short history of speciesism," defining it as "a prejudice or attitude of bias in favour of the interests of members of one's own species and against those of members of other species":
Racists violate the principle of equality by giving greater weight to the interests of members of their own race when there is a clash between their interests and the interests of those of another race. Sexists violate the principle of equality by favouring the interests of their own sex. Similarly, speciesists allow the interests of their own species to override the greater interests of members of other species. The pattern is identical in each case.[11]
Singer argued from a preference-utilitarian perspective, writing that speciesism violates the principle of equal consideration of interests, the idea based on Jeremy Bentham's principle: "each to count for one, and none for more than one." Singer argued that, although there may be differences between humans and nonhumans, they share the capacity to suffer, and we must give equal consideration to that suffering. Any position that allows similar cases to be treated in a dissimilar fashion fails to qualify as an acceptable moral theory. The term caught on; Singer wrote that it was an awkward word but that he could not think of a better one. It became an entry in the Oxford English Dictionary in 1985, defined as "discrimination against or exploitation of animal species by human beings, based on an assumption of mankind's superiority."[12] In 1994 the Oxford Dictionary of Philosophy offered a wider definition: "By analogy with racism and sexism, the improper stance of refusing respect to the lives, dignity, or needs of animals of other than the human species."[13]"
Source:
http://en.wikipedia.org/wiki/Speciesism