As I said, I had trouble finding anything too specific about Kropotkin and money. Correct me if I'm wrong, but in addition to abolishing the state, he apparently wanted to abolish private property, and he fully supported mutual aid. His work, Mutual Aid: A Factor of Evolution (1902) had some interesting things in it.
https://www.marxists.org/reference/archive/kropotkin-peter/1902/mutual-aid/index.htmIt was primarily intended to be a response to the Social Darwinists of the time who mis-used Darwin's theory of evolution to justify the political and economic status quo of their time. And I do mean "mis-used", because it was an improper application of a scientific theory on the development of life to the socio-political structures of mankind. Kropotkin didn't try to argue against it in that way, however. Instead, he thought that undue attention had been given to competition (not that he thought it was entirely wrong), at the expense of the cooperative aspects of life. "Mutual aid" was, in this book, primarily a generic term for cooperative behavior among men.
While he was certainly right about this, what he may not have seen is how much cooperative behavior exists in capitalism, as well. It is perhaps, not given enough stress, but whenever someone talks about division of labor and voluntary exchange, they are certainly talking about cooperative behavior, as well. Finished goods don't just appear on store shelves by magic. It takes many people cooperating, from the people who gather the raw resources, to people who develop and provide the tools for working those resources, to people who distribute them to retail outlets, not to mention the people who transport the resources and goods at the various stages to the necessary locations. Leonard Read's essay, "I, Pencil"
http://www.econlib.org/library/Essays/rdPncl1.html, attests to the extensive cooperation necessary to produce a pencil.
Kropotkin spends a lot of time showing examples of mutual aid throughout the history of mankind, to show that without the State, people still organize spontaneously to solve various social problems and provide certain social functions. But Frederich Hayek also talks much about spontaneous order, arguing that market economies *are* a spontaneous order.
https://en.wikipedia.org/wiki/Spontaneous_orderMost ancaps take it as a given that without a State, people would still find ways to voluntarily organize and deal with various social functions.
Kropotkin's examples of mutual aid tend to be matters of common or customary behaviors and habits, even specifying examples of medieval common or customary law. He mentions Iceland and its medieval legal system at one point, as an example. David Friedman wrote much more extensively about Medieval Iceland and its legal system in the essay: PRIVATE CREATION AND ENFORCEMENT OF LAW: A HISTORICAL CASE.
http://www.daviddfriedman.com/Academic/Iceland/Iceland.htmlCertainly, as an ancap, I think it is inevitable that without the State, society would switch to some form of common or customary law. Furthermore, I don't think that this conflicts with capitalism as I know it. With examples like Merchant Law and modern private arbitration and mediation services existing smack dab in the middle of businesses and business operations, it seems to me that "mutual aid" as Kropotkin called it, is really complementary to capitalism, not hostile towards it. Private Defense Agencies, or PDA's as many ancaps refer to them, may well be for-profit businesses, but they would have to rely extensively upon common or customary legal procedures to successfully operate their businesses.
Charles Rembar is no libertarian, as far as I know, but his book "The Law of the Land",
http://www.amazon.com/The-Law-Land-Evolution-System/dp/0671243225, is an interesting history of the Anglo-American legal system, and spends some time on common law, and how the "King's Law" was greatly increased at the expense of common law as part of the monarchy's power struggles with English barons.
Bruce Benson's, "The Enterprise of Law: Justice Without the State",
http://www.amazon.com/The-Enterprise-Law-Justice-Without/dp/1598130447, is, in my opinion, an excellent book that details how private common and customary institutions can provide law without the state, and contrasts it with the current authorian legal system and how it works. He has much to say about incentives, institutions, and customary legal systems.
Another thing Kropotkin may not have seen is that money itself is a good example of spontaneous order and mutual aid. Money, a medium of exchange, resolved the problems of barter, allowed for greater trade among people, and also provided other social functions as a means of accounting and a store of value. The State didn't create money; it merely appropriated its social functions as it did the other social functions that mutual aid had been providing, as Kropotkin pointed out.
So you can see that there are several things that ancaps can agree with Kropotkin about, and hopefully you can see where Kropotkin's own statements and arguments can be used to defend capitalism, even if he couldn't.
What I haven't found yet in Kropotkin's works is why he was anti-capitalist, although I may eventually come across it. I certainly hope it's more than simply mistaking the existing government-manipulated, mixed socialist/crony-capitalist system as being "capitalism". Many leftists think that capitalism can't work without government, but as you *should* already know, ancaps tend to argue that capitalism would work better (that is, for the betterment of humanity) without government interference.
One problem I see with mutual aid, and why I think it is complementary to capitalism, is that it seems limited in how much it can do. Can we agree that people willingly help other people in times of need or distress, especially if they are people we know, like family, friends, neighbors, co-workers and the like? If so, we can then ask questions that relate to the limitations of mutual aid. How willing are people to help complete strangers, even strangers in distress, people that they know little or nothing about? As a modern example, look at the current backlash against Syrian refugees, a backlash that is occurring not just in the U.S., but in many countries.
A second question is this: if mutual aid is primarily to help people in extreme or uncommon situations, how much help are people willing to provide in the more ordinary or common situations? Perhaps you have had the experience of a friend or relative who lost their home or job and needed a place to stay, "just temporarily". You may have been glad to let them stay at first, but if the days turn into weeks or months, and they still haven't gotten back on their feet, how long are you willing to put with them being freeloaders, contributing little or nothing to your household? At what point do you say you can't help them any more?
Finally, mutual aid doesn't really seem to be an economic system of its own, as it provides little guidance for resource allocation, determining where goods and services are most urgently needed or desired. This is, on the other hand, one of the things that capitalistic markets are good at doing. Voluntary exchange is, of course, non-coercive, and therefore non-oppressive. Division of labor creates an interconnecting network of voluntary exchanges, even among complete strangers, allowing people to help other people be more productive (mutual aid). Concentration of capital allows us to invest in ways to make people even more productive. Financial institutions provide better ways of managing exchanges and to borrow capital so that it can be reinvested in improving productivity.
So as I see it, there's not really too much overlap between Kropotkin's mutual aid and capitalism as I see it; they are complementary, each working in areas where the other doesn't work very well. Kropotkin should have been an anarcho-capitalist, not an anarcho-communist.
