Humans arrived in the Kaliko Islands about 7,000 years ago, and within 3,000 years most of the large mammal species that had lived in the forests of the Kaliko Islands had become extinct. Yet humans cannot have been a factor in the species' extinctions, b

The given argument tries to explain the extinction of most of the mammals in Kaiko islands. While arriving at a conclusion the argument neglects human from being considered as a possible reason for extinction based on the evidences. Finally, it concludes as humans were not the factor it should have been climate and environmental factors. There are certain assumptions on which the argument is built on, if the assumptions doesn’t hold then the conclusion loses its significance.

The argument states that, having found no evidence, humans could have never been in contact with those mammals that became extinct. While arriving at this conclusion the argument assumes that, every possible contact leaves evidences and evidences will always be found and never get defaced. While the initial assumption might be true, the later might not be always true. For example, there could have been a huge environmental change which could have destroyed all the possible evidences . Also, there might be parts of island which are yet to be discovered and might hold the necessary evidences to prove the contact.

While concluding that humans would have never hunted these mammals, the argument assumes that humans always leave the bones after finishing the meal. This assumption is based on the fact that humans left the bones of the fish after the meal. There could be other reasons for not having found the bones of the mammals. For example, we know that humans used to make weapons out of the bones of animals. May be humans then used the bones of the animals for making weapons, or decorating themselves. On the contrary fish bones might have been too fragile to serve this purpose. This being true, it proves the assumption to be wrong and weakens the conclusion arrived.

Finally the argument assumes that, when the possibility of humans being the reason for extinction is taken out, the only plausible explanation could be environment and climatic factors. Well, this could be true, but there is a possiblity that it could have been due to predators or the mammals could have fought against each other and lead to their own extinction. As these possiblities have not been considered or discussed in the provided arguemnt, one can’t conclude that environment and climatic factors alone should have caused the extinction.

With these stated, the argument has its biases and the conclusion that it has arrived is based on these biases. While some of the biases might sound plausible, the conclusion of the argument can be weakend if any of the assumptions are proved to be wrong. Hence, the argument has to support its assumptions with more evidences to further strengthen the conclusion that the argument has arrived with.