Capitalism does not exist in a vacuum but is an expression of a specific intellectual foundation — a particular “integrated, systematic view of existence” — a philosophy. That philosophy is Objectivism: the philosophy of Ayn Rand.
An economic system (in our case, the free-market) does not exist in a vacuum but is the expression of a specific ethical-political-legal foundation.
Economics is not a primary. It is ones legal-political system that sets the ground rules for any economic system. Yet, neither is politics a primary. Politics is the application of ethics to social issues.
What is ethics? Ethics is the science — or branch of philosophy — that defines a code of values that one should live by. It answers the question: “what should I do?” Yet, neither is ethics a primary.
One’s ethics depends on the branch of philosophy known as epistemology. Epistemology (epistēmē is the Greek word for knowledge) is the branch of philosophy that studies the nature and means of human knowledge, of grasping reality; it answers the question: “how do I know it?”
Finally, epistemology depends on the branch of philosophy known as metaphysics. Metaphysics refers to the branch of philosophy that studies the nature of reality (that which is); it answers the question: “what kind of world do I live in?”
In summary, one’s view of what is the proper social system for human beings depends on how one views human nature, and how one grasps the world one lives in. It depends on one’s philosophy — an integrated, systematic view of existence.
Philosophy is important. It is not a mere plaything of ivory-tower professors or a “…bauble of the intellect, ” writes Professor Leonard Peikoff, “but a power from which no man can abstain. Anyone can say that he dispenses with a view of reality, knowledge, the good, but no one can implement this credo. The reason is that man, by his nature as a conceptual being, cannot function at all without some form of philosophy to serve as his guide.”  Philosophy is a matter of life and death.
If one’s philosophy is that one lives in a world of miracles (religion), where truth is by revelation (faith), and morality means sacrificing oneself for others (altruism), one’s politics will be very different from someone who believes in a world of cause and effect (science), that one can understand rationally (reason), to pursue and achieve personal happiness (self-interest).
To concretize this point further, observe that if one’s philosophy is that of a religious fundamentalist then abortion is murder, and a fetus has the right to live in a woman’s body irrespective of the woman’s thoughts on the subject. Life comes from God, and what God giveth let no man (or women) take away. If one is an advocate of unlimited majority rule (democracy), then the individual has no rights but lives by permission of the state (the majority in power at the moment), and the government can revoke (alienate) this permission at whim. The right to abortion becomes a matter of majority vote, i.e., might makes right. If one is an Objectivist, abortion is an inalienable right, since the woman is an actual being — whose body belongs to her — and the fetus is a potential being — a part of the woman’s body — to be disposed of according to the women’s interests.
Politics is an inseparable branch of the tree of philosophy. Separate a fruitful branch from the living tree of good philosophy, and graft it onto the dying tree of bad philosophy and that once fruitful branch will wither, crumble and die. It is on the withered cross of anti-reason, altruistic-collectivist philosophy that capitalism is being crucified.
In philosopher Ayn Rand’s view, the reason why capitalism is attacked and misrepresented (even by its alleged defenders) is because of the anti-enlightenment philosophies that dominate our culture:
“It is often asked: Why was capitalism destroyed in spite of its incomparably beneficent record? The answer lies in the fact that the lifeline feeding any social system is a culture’s dominant philosophy and that capitalism never had a philosophical base. It was the last and (theoretically) incomplete product of an Aristotelian influence. As a resurgent tide of mysticism engulfed philosophy in the nineteenth century, capitalism was left in an intellectual vacuum, its lifeline cut. Neither its moral nature nor even its political principles had ever been fully understood or defined. Its alleged defenders regarded it as compatible with government controls (i.e., government interference into the economy), ignoring the meaning and implications of the concept of laissez-faire. Thus, what existed in practice, in the nineteenth century, was not pure capitalism, but variously mixed economies. Since controls necessitate and breed further controls, it was the statist element of the mixtures that wrecked them; it was the free, capitalist element that took the blame.
“Capitalism could not survive in a culture dominated by mysticism and altruism, by the soul-body dichotomy and the tribal premise. No social system (and no human institution or activity of any kind) can survive without a moral base. On the basis of the altruist morality, capitalism had to be—and was—damned from the start.” 
It is the altruist-collectivist moral base that capitalism must be “saved” from.
Laissez-faire capitalism is a political-economic system that requires a specific philosophical framework. If capitalism is built upon an improper philosophical base, will be like a towering skyscraper built on quicksand.
What is the proper philosophical base? In the words of the American philosopher Ayn Rand:
“It is . . . by reference to philosophy that the character of a social system has to be defined and evaluated. Corresponding to the four branches of philosophy, the four keystones of capitalism are: metaphysically, the requirements of man’s nature and survival—epistemologically, reason—ethically, individual rights, politically, freedom.” 
This site holds that the philosophy that provides a proper foundation for capitalism is Ayn Rand’s revolutionary philosophy: Objectivism.
Objectivism holds that one should live by one’s mind and efforts, in the pursuit of one’s rational self-interest, neither sacrificing oneself to others, nor sacrificing others to oneself (ethics); that one can understand reality by reason and logic (epistemology), as one lives in a world of cause and effect where there are no contradictions (metaphysics). A complete, systematic presentation of Objectivism is beyond the scope of this site. For a complete presentation of Rand’s philosophy, I heartily recommend Objectivism: The Philosophy of Ayn Rand by Professor Leonard Peikoff. This book is required reading for all advocates of capitalism.
 Leonard Peikoff, Objectivism: The Philosophy of Ayn Rand
 Ayn Rand, “What Is Capitalism?” Capitalism: The Unknown Ideal, 30