Although vivisection literally means 'to cut up alive', the term has come to include all experiments involving animals, and not just those involving dissection. Call it what you will, animal experiments are always cruel, causing psychological and/or physical suffering to all of its victims.
Vivisection cannot be justified neither ethically nor scientifically. Those who practice vivisection - and accuse their opponents of being "sentimental" toward animals - tout the self-serving presumption that the question ultimately boils down to "animals' lives instead of yours". By contrast, antivivisectionists consider the vivisectors' stock question "Would you prefer to save a mouse or a child?" to be meaningless. Instead, they ask: "Why not strive to save both? Why be forced to choose between two evils?"
Science based on the principle that the end justifies the means can easily justify performing atrocities on human and non-human animals; for the highest ends can be attained by the lowest means. Vivisection is thus bad science. In the words of the 18th century English philosopher, Jeremy Bentham:
"The problem is not 'can they reason?' nor 'can they speak?' but 'can they suffer?'"
Obviously, if humans were to be subjected to vivisection, the amount of pain they would feel would certainly not depend on their communication skills nor on their ability to solve differential equations - suffering is the same for geniuses and dunces. Likewise, non-human animals suffer in the same ways and to the same degree as humans. Those who provoke the suffering are criminals - whether their justification is that they are helping humanity or helping their own careers!
1-2.
Britches, the monkey liberated from the University of California
at Riverside laboratory by the Animal Liberation Front (ALF) in 1985. The
vivisectors had sewn the baby monkeys' eyelids together and grafted a
sonar device onto her head.
Courtesy of P.E.T.A. (1980's-1990's)
3.
Chick
with electrodes implanted into his brain. The photo was taken
by an Animal Liberation Front (ALF) activist during a raid on the Institut
National Scientifique de'Etude et de Recherche Medicale in Paris, and
published by the French animal rights organization, Aequalis. Although no
punishment would ever be meted out to the vivisectors, the head of
Aequalis was tried, sentenced, and fined $15,000 for his "crime".
Photo given by the American Association P.E.T.A. (1990's)
4.
The head of a vivisected cat preserved in formaldehyde by the very
vivisector who had experimented on her vocal chords
(Boys Town Hospital, USA, 1996)
Photo given by the American Association P.E.T.A.