Sometimes money is compared with the blood of the economy. The credit crisis painfully demonstrated that the economy depends on a permanent infusion of credits. As soon as the banks deliver a bit less credit, enterprises fail and the mass dismissals succeed each other.
We are made to believe that the problems with the subprime mortgages were an incident. With a giga-capital injection, a bit more rules and better supervision the banking system would function correctly again. And oh yes, we must trust the banks again.
Main cause of the credit crisis
The main cause of the credit crisis lies in the bank/money system itself. The principle of the money system is that money is brought into circulation by supplying credit and vanishes again at the moment the credit is paid back. Western banks use two game rules: 1. in comparison with the lent out amounts, they have to dispose of only 8% own capital. ; 2. they have to keep a small percentage of reserves in their pay-desk to perform payments for their customers and to hand out cash money.
With these two rules the major part of the money that customers have in their checking and savings accounts, is lent out (at Triodos bank this is 65% , at most other banks much more.) The lent out money is spend by the borrower and subsequently arrives in accounts at other banks. The customers of the first bank now still dispose of their bank balance, while at the receiving banks new bank balances have been created. These new bank balances are pretext to supply new credits. This goes on and on. The bank balances are multiplied each time.
This system is called "fractional reserve banking".  The banks can fulfil only a fraction of their commitments. They have lent out their customers' money, although this money can be claimed immediately. They just gamble that customers will never claim more than they have reserves in their pay-desk and that, if needed, the central bank will come to their rescue. The percentage that banks are not allowed to lend out (the so called cash reserve) can be determined by law (in the US it was 1:9). In many other countries the central bank dictates the minimum percentage. Before the crisis, for the Netherlands, I have read a cash reserve percentage of only 3%.
Each time a borrower spends the money of his loan, the money moves to a following bank that takes advantage of it to lend out most of it. So, the same money is lent out over and over again. In a 1:9 system the same money can be lent out 9 times. With a cash reserve of 3% it can be lent out 32 times. And each time when it is lent out, a bank collects interest.
The classical risk for banks is that loans are not paid back. That risk increases, when less new loans are put into circulation than those that are paid back. Then the available money in the country decreases. For the banking industry an environment in which the money supply permanently grows has less risks. The central bank sees to it that the money supply keeps growing (the so called 2% inflation.) When needed, banks can borrow from the central bank, with stocks or bonds as collateral. When the government borrows money, the amount of money in the country increases too. Of course, the biggest increase is caused by the multiplier factor that banks realize themselves. When the multiplier factor rises, loans can be paid back more easily. The income of the bank rises too. So there is a natural tendancy to lend out higher percentages each time. The banks can also impose more and more requirements to the borrowers to lower the risks. However, the consequences of this dynamic is that the cash reserves decrease.
The purpose of the cash reserves is to supply cash money to the customers and, mainly, to perform payments between the accounts at different banks. When a customer of bank A makes a payment to an accountholder at bank B, a bit of the cash reserve of bank A moves to bank B. And as soon as a customer of another bank makes a payment to a customer at bank A, it highers its cash reserve again. So, the money goes forward and backward between the banks. In the past, it could take three days to make a payment to a customer at another bank. Banks needed quite a lot of cash reserves. Since then, the payment system has been modernized. Payments go to the destination bank still the same day. The same money can serve thousands of times for payments between banks each day. For mutual clearance of payment orders only a little cash reserve is needed today. The banks have also taken care that their customers merely need bank notes (cash) anymore. At first, employers were obliged to pay wages in bank accounts. Everybody got checks, forms for payment orders, followed by plastic payment cards and internet banking. In the Netherlands, since a few years, the debit card is more and more imposed for all small expenses. For each euro we don't keep in our pocket, the banks can lend out a multiple amount...
Although a growing money supply is needed to lower the risk of system crashes by failing loans, the multiplier factor ends up causing more and more instability in the money supply and causing smaller cash reserves. As soon as a bank has to book a loss, this not only decreases its capital, but often also its cash reserve. When a bank has less than the 8% required capital (compared to the outstanding loans), or too little cash reserve left, then, according to the rules, the bank has lost the game. The subprime mortgages caused the system to get stuck in 2007, but, in fact, any somewhat bigger losses, like for instance on Third World loans, could have triggered the crisis. The banks simply had too few reserves left to take losses. And once one bank gets in trouble, it can easily spread to other banks, because banks borrow money and buy securities from each other to optimize their balance sheets. The fact that the subprime mortgages were wrapped up as a complex financial product only made the effect bigger. But the main cause of the crisis is not the loss on the subprime mortgages, but the structurally decreased capacity of banks to take losses. And that is the consequence of the natural dynamic within the "fractional reserve banking" system.
In many countries the governments were called for help to save the banks. This is remarkable, for the banking system functions outside any democratic control. The directors of central banks took the ministers of finance to international meetings (or took them in) and extracted inconceivably high loans for the banks. All of us we are guarantors with future tax money. However, the banks would pay a market conform interest on these loans. To put it otherwise, they will charge their customers for it: you and me. In fact the ministers of finance were put against the wall. The banks were not allowed to fail; they were too important.
The power over the money has been given away by members of parliament in the past. They had no idea about what money was and how the system worked. Now the banks determine how much money there is in circulation and how much the population must pay for this service. The multiplier factor of money also leads to a shift in power within the country: banks make more and more investment decisions and the government all the time less. And because there is more and more money available, more and more things become buyable. This has led, for instance, to the dismantling of many state tasks. Services that are important for the functioning of society, like public transport, post, telephone, water and energy supply have been thrown in the hands of the financial benefit seekers. Private companies would perform better. But in fact, it hides a shift in power due to the "fractional reserve banking".
We still pretend that we live in a democracy, but the parliament has no say anymore over money, one of the most important factors in society. To get the power over money back inside the democracy only small law changes are needed. Unfortunately, today's parliamentarians, except a very little number of them, still don't understand nothing about the money system. That is a pity, because by taking back the power over money and with an adequate bank reform, they would be able to stop the credit crisis almost immediately. 
Described in short, this bank reform could show like this: the central bank becomes a state bank, part of the ministry of finance. The state bank is the only bank that creates money for loans. The parliament decides which sort of loans must get priority in the interest of society. These loans can be supplied at favorable conditions. This way, the parliament gets much more influence over the shaping of society.
Todays' commercial banks become server counters for the loans from the state to the public. They manage the checking and savings accounts of their customers on behalf of the state bank. They cannot dispose freely anymore of this money and cannot multiply the balances. However, they will be allowed to collect funds to lend out.
When the treasurer of the local sports club would use the money unseen to invest it and enrich himself this way, he takes the risk to be condemned. But when bankers manage the money in our checking accounts this way, they go free.
The corrupt rules for banks have originated long ago, when gold smiths, and later bankers, were bent upon fooling their customers.  The only difference with before is that the system has now become official and the law allows it. Of course, this practice is kept secret as much as possible. You will not find any website of a bank or of a central bank, explaining clearly how a bank works and how the system functions. At schools - except for a few very rare exceptions - the subject is not treated, and even in most economy studies it is not part of the program.
In particular from 1913, after the establishment of the Federal Reserve Bank in the US, the bankers have succeeded to obtain an own legal framework in many countries and seize the power over the local money. In each of these countries one bank got the role of the central bank. The names of these central banks keep up the appearance that they would be governmental bodies, whereas, on the contrary, they became independent from the local parliament and government, be it step by step sometimes: De Nederlandse Bank N.V. (1914), Bank of Canada (1935), National Bank of Danmark (1936), Deutsche Bundesbank (1957), Banque de France (1993), Bank of Japan (1997) and so on. On their bank notes, there were often portraits of kings and statesmen. In many cases the appearance that money would be of the state was corrobated by the fact that the state kept the responsibility to mint coins. On the coins too, there were often trustworthy portraits. When necessary, even religion was used. The Dutch guilder coin had the inscription "God be with you" in the side.
Eternal economic growth
It is thanks to the potential for economic growth and the increasing availability of raw materials and energy during the last century that the money multiplier did not lead to problems, but even pushed the economic growth.
My thesis is that today's bank system is a danger to the future of humanity. The permanent inflation, which is inherent to this system, forms an impulse for ever more economic activity in order to compensate for the loss of value of the money unit and to obtain a bit of the additional money put in circulation. In my opinion, this is also where the stubborn believe comes from that an economy must grow to be healthy. (And not, for instance, from a spontaneous desire of the working class to work harder all the time.)
Sustainability, on the contrary, supposes an equilibrium with our environment. Our environment does not grow along with the increase of our economic activity and population. It is destroyed by it. 
We need to get rid of our inflationary banking system as soon as possible and put the power over money back where it belongs in a democracy: in the parliament.
Rudo de Ruijter is an independent researcher from the Netherlands. The author can be contacted via the website: www.courtfool.info.
 The 8% capital requirement is the standard from the Basel Accords of 1988, on which all kinds of exceptions apply. This way, for loans with mortgages on housing, banks only need to have a counterpart of capital equal to 4% of the outstanding loans. For loans to other banks the requirement is still lower most of the times and for loans with a state guarantee it is 0%. http://www.bis.org/publ/bcbs04a.htm & http://www.bis.org/publ/bcbs04a.pdf?noframes=1
in 2004 the European Commission proposed to lower the 8% to 6% and the 4% to 2.8%.
The Basel II Accords of 2006 offer more possibilities to (big) banks to choose the most favorable method to determine their risks. http://www.bis.org/list/bcbs/tid_22/index.htm
 At Triodos Bank 65% is lent out.
 http://www.mises.org/story/2882#3 see chapters Fractional Reserve Banking, Central Banking, Deposit Insurance. Note that Murray N. Rothbard (1926–1995) was a defender of the return of the gold standard, like, for instance, Ron Paul still is. Although understandable, seen from a historical US' perspective, a money system based on gold has many disadvantages. Countries without gold mines would have to buy gold (which means deliver goods and services to the gold mining countries) for the only purpose of disposing of a national means of payment. Each time when more gold comes on the market, they will be obliged to buy more of it, to prevent their currency to devaluate against currencies of countries with increasing gold stocks. The gold mining industries would, in many aspects, get supra-national power, even more than the Fed today. Gold has no stable value. Its pricing can be influenced by holders of big stocks, like the gold mining industries and central banks. Even big numbers of small buyers and sellers, when triggered by fear or greed, can influence its price. All these price fluctuations can form a danger for any economy that has its money pegged to gold. Still more than today, gold would trigger conflicts, oppression and wars.
 Bank crisis? Reform!
 Secrets of money, interest and inflation.
 Energy crisis: turning-point of humanity.