1.-  Immanuel Kant 

Immanuel Kant was born in 1724 in Königsberg, the capital of Prussia at that time, today the city of Kaliningrad in the Russian exclave of Kaliningrad Oblast. He was the fourth of eleven children (four of them reached adulthood). Baptized ‘Emanuel’, he changed his name to ‘Immanuel’[4] after learning Hebrew. In his entire life, he never traveled more than a hundred miles from Königsberg.[5] His father, Johann Georg Kant (1682–1746), was a German harnessmaker from Memel, at the time Prussia’s most northeastern city (now Klaipėda, Lithuania). His mother, Regina Dorothea Reuter (1697–1737), was born in Nuremberg[6]. Kant’s grandfather had emigrated from Scotland to East Prussia, and his father still spelled their family name “Cant.”[7] In his youth, Kant was a solid, albeit unspectacular, student. He was raised in a Pietist household that stressed intense religious devotion, personal humility, and a literal interpretation of the Bible. Consequently, Kant received a stern education – strict, punitive, and disciplinary – that preferred Latin and religious instruction over mathematics and science.[8]

  • The young scholar

Kant showed a great aptitude to study at an early age. He was first sent to Collegium Fredericianum and then enrolled at the University of Königsberg (where he would spend his entire career) in 1740, at the age of 16.[9] He studied the philosophy of Leibniz and Wolff under Martin Knutzen, a rationalist who was also familiar with developments in British philosophy and science and who introduced Kant to the new mathematical physics of Newton. Knutzen dissuaded Kant from the theory of pre-established harmony, which he regarded as “the pillow for the lazy mind”. He also dissuaded the young scholar from idealism, which was negatively regarded by most philosophers in the 18th century (The theory of transcendental idealism that Kant developed in the “Critique of Pure Reason” is not traditional idealism, i.e. the idea that reality is purely mental. In fact, Kant produced arguments against traditional idealism in the second part of the “Critique of Pure Reason”). His father’s stroke and subsequent death in 1746 interrupted his studies. Kant became a private tutor in the smaller towns surrounding Königsberg, but continued his scholarly research. 1749 saw the publication of his first philosophical work, Thoughts on the True Estimation of Living Forces.

Kant is best known for his transcendental idealist philosophy that time and space are not materially real but merely the ideal a priori condition of our internal intuition. Also, he made an important astronomical discovery, namely the discovery of the retardation of the rotation of the Earth, for which he won the Berlin Academy Prize in 1754. Even more importantly, from this Kant concluded that time is not a thing in itself determined from experience, objects, motion, and change, but rather an unavoidable framework of the human mind that preconditions possible experience.[citation needed]

According to Lord Kelvin:

Kant pointed out in the middle of last century, what had not previously been discovered by mathematicians or physical astronomers, that the frictional resistance against tidal currents on the earth’s surface must cause a diminution of the earth’s rotational speed. This immense discovery in Natural Philosophy seems to have attracted little attention,–indeed to have passed quite unnoticed, –among mathematicians, and astronomers, and naturalists, until about 1840, when the doctrine of energy began to be taken to heart.

Lord Kelvin, physicist, 1897

He became a university lecturer in 1755. The subject on which he lectured was “Metaphysics”; the course textbook was written by A.G. Baumgarten.

According to Thomas Huxley:

“The sort of geological speculation to which I am now referring (geological aetiology, in short) was created as a science by that famous philosopher, Immanuel Kant, when, in 1775 [1755], he wrote his General Natural History and Theory of the Celestial Bodies; or, an Attempt to Account for the Constitutional and Mechanical Origin of the Universe, upon Newtonian Principles.” —

Thomas H. Huxley, 1869

In the General History of Nature and Theory of the Heavens (Allgemeine Naturgeschichte und Theorie des Himmels) (1755), Kant laid out the Nebular hypothesis, in which he deduced that the Solar System formed from a large cloud of gas, a nebula. He thus attempted to explain the order of the solar system, seen previously by Newton as being imposed from the beginning by God. Kant also correctly deduced that the Milky Way was a large disk of stars, which he theorized also formed from a (much larger) spinning cloud of gas. He further suggested the possibility that other nebulae might also be similarly large and distant disks of stars. These postulations opened new horizons for astronomy: for the first time extending astronomy beyond the solar system to galactic and extragalactic realms.[10]

From this point on, Kant turned increasingly to philosophical issues, although he continued to write on the sciences throughout his life. In the early 1760s, Kant produced a series of important works in philosophy. The False Subtlety of the Four Syllogistic Figures, a work in logic, was published in 1762. Two more works appeared the following year: Attempt to Introduce the Concept of Negative Magnitudes into Philosophy and The Only Possible Argument in Support of a Demonstration of the Existence of God. In 1764, Kant wrote Observations on the Feeling of the Beautiful and Sublime and then was second to Moses Mendelssohn in a Berlin Academy prize competition with his Inquiry Concerning the Distinctness of the Principles of Natural Theology and Morality (often referred to as “the Prize Essay”). In 1770, at the age of 45, Kant was finally appointed Professor of Logic and Metaphysics at the University of Königsberg. Kant wrote his Inaugural Dissertation in defence of this appointment. This work saw the emergence of several central themes of his mature work, including the distinction between the faculties of intellectual thought and sensible receptivity. Not to observe this distinction would mean to commit the error of subreption, and, as he says in the last chapter of the dissertation, only in avoidance of this error will metaphysics flourish.

The issue that vexed Kant was central to what twentieth century scholars termed “the philosophy of mind.” The flowering of the natural sciences had led to an understanding of how data reaches the brain. Sunlight may fall upon a distant object, whereupon light is reflected from various parts of the object in a way that maps the surface features (color, texture, etc.) of the object. The light reaches the eye of a human observer, passes through the cornea, is focused by the lens upon the retina where it forms an image similar to that formed by light passing through a pinhole into a camera obscura. The retinal cells next send impulses through the optic nerve and thereafter they form a mapping in the brain of the visual features of the distant object. The interior mapping is not the exterior thing being mapped, and our belief that there is a meaningful relationship between the exterior object and the mapping in the brain depends on a chain of reasoning that is not fully grounded. But the uncertainty aroused by these considerations, the uncertainties raised by optical illusions, misperceptions, delusions, etc., are not the end of the problems.

Kant saw the mind could not function as an empty container that simply receives data from the outside. Something had to be giving order to the incoming data. Images of external objects have to be kept in the same sequence in which they were received. This ordering occurs through the mind’s intuition of time. The same considerations apply to the mind’s function of constituting space for ordering mappings of visual and tactile signals arriving via the already described chains of physical causation.

  • The silent decade

At the age of 46, Kant was an established scholar and an increasingly influential philosopher. Much was expected of him. In response to a letter from his student, Markus Herz, Kant came to recognize that in the Inaugural Dissertation, he had failed to account for the relation and connection between our sensible and intellectual faculties, i.e., he needed to explain both how humans acquire data and how they process data—related but very different processes. He also credited David Hume with awakening him from “dogmatic slumber” (circa 1770). Kant did not publish any work in philosophy for the next eleven years.