Kant was born in Konigsberg; he spent his life there; he died there. At the age of forty-six, Kant received an appointment as a professor of logic and metaphysics at his alma mater the University of Konigsberg. His famous claim: "Though our knowledge begins with experience, it does not follow that it arises out of experience." A philosophical classic is his work Critique of Pure Reason wherein he asserts that our perceptual apparatus is capable of ordering sense-impressions into intelligible unities, which, while in themselves cannot be proven, we are led to conclude through "pure reason," that intelligible unities, such as God, freedom, and immortality, do exist; and that the formation of such intelligible unities are practical necessities for one's life. An admirer of Rousseau, Kant's work gave rise to the Idealist school (Fichte, Hegel and Schopenhauer).
Kant was of the view that while the existence of God could not be proven, we ought to come to a belief in God's existence by way of "logical understanding." Kant concluded that this world was not sufficient in itself, that an external power, which he identified with God, was a regulative necessity; and that God was a requisite for morality, it gives meaning to our life here on earth. The existence of God was, for Kant, but one of three postulates of morality, the other two being freedom of the will, and immortality of the soul. These moral axioms, unprovable as they are, existed for Kant simply because they were the sine qua non of the moral life. (So much for the notion that morality is something that arises from our own character, from our own intelligence: - I would argue that the acceptance of an external, all powerful being reduces us to mere servants; and, thus, there is no need for morals, there is but only the need to obey.)
Kant would not categorize himself as a "dualist," such as was Plato (one who believes that there is a world beyond the material world that we perceive, one that places the soul or mind of a human in this other world, that the soul or mind is a non-material entity), he took a more extreme step; none of reality exists; reality and all that is in it, including human beings are part of this other world, all part of a dream world (see Schopenhauer).
To those who cannot accept such a speculative and theoretical philosophy as Kant's might, however, through his writings obtain an insight into the workings of the real universe in which we live. I quote from Paul Johnson's book, The Birth of the Modern:
"The 18th century had failed to solve the problem of how heat, light, magnetism and electrical power fitted into the laws of motion and attraction Isaac Newton had set out in his Principia (1687). But Immanuel Kant, in his Critique of Pure Reason (1781) and still more in his Metaphisical Foundations of Natural Science (1786), had produced an inspirational insight. He was concerned not so much with science as with God. Was there a duality, of spirit and matter? Newton had been concerned only with matter -- and with the advance of science, this pointed to a materialistic world and led to atheism. Kant wanted to bridge the gulf between spirit and matter and harmonize the physical and moral laws. As he saw it, space and time were purely mental intuitions which made our grasp of external reality possible. The substance of thing-in-itself, Ding an sich, was hidden from human reason -- reality was perceived, rather than led an independent existence. We perceive reality only through the forces, of attraction and repulsion, which work in space. Hence Kant dismissed the dualism of spirit and matter, replacing it by forces. The universe consisted, then, not of matter but of forces. Electricity, magnetism or any other observable effects were governed by laws of attraction and repulsion within a unified theory of forces, all of which were convertible into one another.
"It is doubtful if the physical scientists could have proceeded as fast as they did in the early 19th century without this essentially metaphysical intuition.
"Coleridge explored the Kantian insight: 'The universe was a cosmic web', as he put it, 'woven by God and held together by the crossed strands of attractive and repulsive forces.' All forms of energy must be convertible; they were also indestructible. 'What,' he wrote to Tom Poole, ' what if the vital force which I sent from my arm into the stone as I flung it in the air and skimmed it upon the water - what if even that did not perish?' Coleridge had thus stumbled upon what was to become the Principle of Conservation of Energy.
"Volta's discovery that the source of electric power was contact between two metals in a solution enabled him to build his pile [battery] in 1800.
"The next stage was to put to the practical test the quasi-metaphysical concept of Kant and Coleridge that the world was governed by forces which were fundamentally indivisible and indestructible, based upon the principle of attraction and repulsion, of which electricity and magnetism were expressions. The Danish scientist Hans-Christian Orsted had been working on Kant's notions for 20 years, and by winter 1819-20, he was able to describe the workings of electromagnetism, or the magnetic field." (Johnson, pp. 551-3.)