This book wants to bring the reader into immediate contact with real philosophizing.1 This reality is the encounter with the great philosophers. What one calls their teaching is part of their life and brings forth life in those who listen to them.

One enters into the thought of the great philosophers, if, by passing through the intellectual foregrounds, one renews within oneself the motivations that once guided those thoughts. Only in such reconstructing, the heartbeat of philosophy becomes perceptible. Thinking dries up in detached didactic pieces, and can then so to speak only be kept in the herbarium of philosophical concepts.

I have dared to disregard here all historical development. For the great philosophers meet us as contemporaries in the space of one single present-day of, as it were, three millennia, to contribute to the lasting task of the human being within time. We want to behold them as such contemporaries in the timeless space of appertaining to each other. Provided that we confront them with one another in an unhistorical way, they become more distinct to us. To be sure we want to have them in front of our eyes, as Dante saw them in limbo, promenading and talking with one another, and want to listen to their conversations. Yet this is denied to us. They meet us in this, our temporal world, into which we bring them to us into the present time through their legacy. Despite all passionate struggles, they are a great community of fellows. We want to enter their realm as the ones who listen, learn, and love, to acquire the right of domicile to the extent to which we ourselves take this task seriously.

Right from the outset, I want to tell to the reader who engages with this book, onto which philosophical ground he will find himself:

Nowadays, two kinds of philosophy are differentiated: one is antagonistic to science, and with only partial justification, the so-called German idealism and modern existentialism are seen as such, and one is scientific (as one sees it in positivism, pragmatism, and in logistic). However, when understood in such ways, both sides are no longer philosophy. This inspiring designation that comes from the Greeks, should not be usurped for something entirely different. Philosophy is in league with the sciences, without being science in itself.

Erstwhile philosophy arose from the will, to comprehend truth through thinking that was hitherto hidden in myth and literature. Only late in the Occident, since the end of the Middle Ages, the specificity of modern science accrued, by which the world of humans became completely revolutionized. Knowledge that is not merely methodical, but is compelling and universally valid and has proven itself factually, is differentiated from all former philosophy, for everyone who understood it will also recognize it, and so it can be disseminated identically throughout the entirety of humankind.

The thinking of philosophy could become only thereby conscious of its original character. To elaborate on this character in a pristine mode is the task of philosophy. As philosophy became methodically conscious of its unique thought in contrast to the knowing in the modern sciences (yet until today this task is not yet sufficiently completed), its fate was on the one hand to be uncomprehendingly disdained, on the other hand to think foolishly that it could dispense with the sciences. True philosophy, however, is by virtue of being tied to science more than science.

The connection becomes discernible in such way that nowadays true philosophizing will not be possible to anyone who is not at home in the sciences. Today, no philosopher can achieve a clear and truthful manifestation of his thinking merely from the origins of philosophizing and without the disposition of scientificity. The contempt for the sciences becomes an act that goes against truth. Without science, no one can have an impact favoring pristine reason, upon which our well-being depends, admittedly this reason can take each step only with the assistance of the intellect, but it is incomprehensible to intellect itself.

The positing of being "more than science" resides in that reason. It constitutes philosophical thinking, it comes from it, it brings the unfolding of reason, where it is comprehended it enhances reason in the world. Philosophy that is inimical to science and reason is erroneous philosophy. By not seeing through oneself, raising superhuman claims with astonishing fancies deriving from truthdreaming and aberrance, reasoning creates harm or justifies it. Yet the philosophical thinking of reason is indeed an expression of unconditional truth; however, it is not straightforward in the manifestation of what is already thought. Unlike the sciences it is not universally valid and will never be equally accepted by all. While intellect seeks the universally true as the one, and also finds it within limits, reason is the one but only as movement and enablement, and not as the content of a sole truth. The rational discussion in the sciences (a discussion that also does not disappear in philosophizing) is replaced by the conflict of the forces, in which the multifariousness of communication of philosophical reason takes place. The results of knowledge in scientific discussion are substituted in philosophical communication by the elucidation of one's existence.

In the sciences there is the tremendous process of advancement. However, the philosophy of the great philosophers is always on a level that cannot be surpassed. The change of philosophy in its appearances is, among other factors, also conditioned by the advancement in the sciences, albeit without being itself a process of scientific advancement. Thence, whereas the history of the sciences is only of incidental interest to science, the history of philosophy is of indispensable interest to philosophy. This indispensability, however, can be seen only by not portraying the history of philosophy as a series of opinions derived from millennia of years, be it as errors that are by now surpassed, be it as accuracies that may be retained. A history of philosophy, understood as a history of the sciences, is no longer a history that is essential for philosophy.

—One might say that there has never been before such a history of philosophy as an introduction to philosophy as I attempt it with this book. Vast amounts of texts and traditions have been accumulated as materials. But contrary to the leveling in encyclopedias one needs to behold the greatness of the philosophers. It was believed one can see through this history and to have an overview based on Hegel, the ingenious yet administrating system builder of the one history of philosophy, as the becoming of the currently reached culmination. However, in contrast to a historical totality it is necessary to behold the encompassing originality of these great ones together with whom we step out of history and into a presentness of being human.—History of problems and history of systems had been pursued and many factual references for terminologies had been worked out. But in contrast to this objectification it all depends on getting to know the fundament of questions and answers within the philosophical origin and to differentiate them from the merely intellectual movements in which thoughts are developed into the infinite as an expression of putatively absolute facts.—The ages in and sociological conditions under which the philosophers lived were put into focus, and they were understood as representatives of their time and culture. However, what matters is to understand that philosophers thought and lived no less against as well as with their time, and above all within their time, and reaching beyond all time. All those methods of philosophic-historical comprehension make good, definite, yet secondary sense. They served me only occasionally as a means.

My unhistorical grouping of the great philosophers seems to me in certain regards as illuminating, yet it is not the only possible one and it is not decisive for its characterization. For each philosopher is himself and bursts the ordering, into which one always unjustifiably wants to subsume him. What matters here is to understand in depth, as it were, each of these great ones (and in an interpretative and ongoing mode this is to be continued into the infinite), to look up to him, not erroneously surveying him.

The great philosophers only begin to speak authentically when we take them out of the historical groupings, so that they as themselves are at hand for us. No longer being in the familiar referencing and ordering, they are only now taken entirely seriously, as if they were directly and emphatically talking to us from the origin. Then they are not listened to in the shadow of a putatively historic survey of knowing-it-all, according to an, in each case, incorrectly presumed highest current vantage point. Philosophy matters to us as itself in its own strength, which comes to us through the great philosophers, not as historical knowledge of it.

Why? This is because the great thinkers, being humans in the world, help us coming to ourselves through the contemplation of perennial matters.

May the world thereby pertain to itself in its becoming or may it disappear in the actual being as appearance and mere transition; may a human heighten toward selfhood in each instance as an individual, unique, irreplaceable one or being absorbed in an encompassing unsubstantial self; may the opposite find its voice in countless other forms— perhaps that which rationally contradicts itself in definite sentences can be unified at all times in existential philosophizing. This thinking irrupts in a seizing mode on us, so that we find thoughtfully our way, which we no longer plan and make with our intellect, but elucidate it with our reason. We ought to assure ourselves, what and wherein we are, and to allow being challenged by internal action rather than intellectual thought.

This book wants to inform about facts, concepts, and intellectual operations, and insofar wants to be a textbook. However, it wants to guide to a personal encounter with the thought of the great philosophers by selecting significant materials, and insofar wants to be a philosophical reading book that induces self-reflection.