Peter on Peter:
I've mentioned both Kropotkin's view of human sociobiology and Peter Marshall in previous posts here. What follows are some quotations from Marshall on Kropotkin's view of "human nature". The sources are available in the notes.
1)Here's Marshall on Kropotkin's inspiration for his ideas:
"Kropotkin's views were first inspired by a lecture delivered in 1880 'On the Law of Mutual Aid' by Russian zoologist Karl Kessler, who argued that mutual aid is as much a law of nature as mutual struggle, but the former was much more important in the progressive evolution of the species. Kropotkin went on to argue that there is far more evidence in nature of co-operation within a species than of competition. In his most famous work, 'Mutual Aid' (1902) he suggests with a rich array of data that in the struggle for life mutual aid appears to be a rule among the more successful species and argues that it is the most important factor of evolution. " (1)
Molly's aside: This sort of thing is, of course, impossible to quantify even in the crude semi-quantitative manner of "more important". Kropotkin recognized that there was indeed "competition" amongst individual members of a given species. He wouldn't have been a Darwinist otherwise. But his extreme group selectionist views led him to look at the species level in a far greater focus than it deserved. It should also be noted that there is an extreme difference between most of what is called competition and what is called "agonistic" ie aggressive behavior. Neither the giraffe's neck nor the peacock's tail (to give examples from resource access selection and sexual selection) involve any agonistic interactions.

2)Here's Marshall again on Kropotkin's view of the "unit of selection"
"Kropotkin makes clear that the struggle for existence which takes place is a struggle against adverse circumstances rather than between individuals of the same species. Where the other Social Darwinists argued that the struggle between individuals leads to the survival of the fittest, Kropotkin asserted that the unit of competition is the species as a whole and that the species that has the greatest degree of cooperation and support between its members is most likely to flourish." (2)
Molly aside: Point taken and pointed out above.
3)Here's Marshall on how these views integrate with Kropotkin's anarchist views:
"Kropotkin did not hesitate to apply these observations of the animal world to the human species. he maintains that society is a natural phenomenon anterior to the appearance of man, and man is naturally adapted to live in society without artificial regulations. man is and always has been a social species. ...Unbridled individualism is therefore a modern growth. ...Evolutionary theory, if properly understood, will not justify the inevitability of capitalist competition or the need for a strong State but rather point to the possibility of anarchy." (3)
Molly aside: But only the "possibility". Kropotkin was, to say the least, "overoptimistic", and he usually believed that the trends that he observed in society were progressive in nature and almost certain to overwhelm other authoritarian trends. Kropotkin has a better "prediction index" from his view of science as a process of induction than the almost 100% wrong record of Marx's from his viewpoint of "science" (sic) as deductions from Hegelian wordplay, but Kropotkin more often than not let his desires get in the way of his inductions.
4)Finally, there is Marshall on Kropotkin's view of what is actually the "proximate cause" of mutual aid:
"Kropotkin rejected both religious and utilitarian ethics in favour of a third system of morality which sees in moral action 'a mere necessity of the individual to enjoy the joys of his brethren, to suffer when some of his brethren are suffering; a habit and a second nature , slowly elaborated and perfected by life in society." (3)
Molly aside: As will be made plain by future posts Marshall doesn't agree with Kropotkin's views. Marshall is actually close to being a believer in the "blank slate" theory of human nature. Also Kropotkin was presenting his views at a time when neurobiology and sociobiology barely existed. At least the outlines of the "roots of empathy", as the proximate cause behind the evolutionary psychology "cause" of cooperation, are much clearer today than they were in the days of Kropotkin.
More on Peter on Peter in future posts.

Molly Notes:
1)Demanding the Impossible: A History of Anarchism. Peter Marshall, Fontana Press, Great Britain 1993, pp 318-319.
2)Ibid, p 319.
3)Ibid, pp 321-322.

More later,
Molly