animals have shown that they can understand concepts such as happy, sad, good, bad, harmful benefitial; certain animals have shown mathematical ability; yes they have taight gorillas basic math and chimps have even been shown to do basic algebra (5 + 3 = X, 1 + X = 9, find X); dolphins have been known to save humans from drowning, and sharks.
Animals do use reasoning. ("hey, my master's is home, I am hungry, if I go ask him for food, he might give me some, because he has before in the past.") its the same reasoning we use to get out of bed everyday. ("I need to go to work to make money to buy food because Im hungry")
Who's to say instinct isn't the EXACT same thing as reasoning; just because when we think, words go throough our heads, instead of ideas, feelings, memories, images and experience as does with animals, means we "think" but animals do not? Sure, our brain capacity and cognitive process may be more complicated, but its a relatively blanketing and assumptive statement to say "animals do not use reasoning or logic" because they do.
A chimp reasons that if I put a stick into a termite mound, "I'll be able to get at them without getting bitten all over on my hand". Or, "This rock can break this nut to get at the good insides (there are even birds that do the same thing). A chimp uses the logic of trial and error; yes, it may have been taught by their progenitors, but when it first happened, the reasoning had to come from somewhere; the mind of the animal. Instinct, logic, thought, cognitive reflex, all stem from this culmination of millenia of inherited experience and existence.
if I am sad, my cat somehow knows it and tries to cheer me up. ~shrug~
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and reptiles are quite a diverse kingdom of animalia; they are not near to being close to the same. And Iguana shares less dna in common with a taipan than humans share with chimps....