Think by Simon Blackburn Chapter 7c The World
Idealism Despite the power of Berkeley s critique, his resulting metaphysical view is highly problematic. Essentially, Berkeley concludes that there is no such thing as an objective physical reality at all. Reality is ideas and nothing more. This view is called idealism.
Avoiding subjective idealism Berkeley s view seems to be equivalent to the kind of solipsism or subjective idealism that Descartes was left with after the failure of his project in the Meditations. Moreover, it seems to imply that in absence of any sentient beings there would be no universe at all, which strongly conflicts with scientific view that sentient beings evolved from a pre-existing universe and that this universe will continue to exist when we are gone. Berkeley tried to solve this problem by invoking God as an infinite mental or spiritual substance, that is constantly perceiving everything.
2 limericks Critique There was a young man who said God, must find it exceedingly odd when he finds that the tree continues to be when noone's about in the Quad. Reply Dear Sir, your astonishment's odd I'm always about in the Quad And that's why the tree continues to be Since observed by, yours faithfully, God
George Berkeley was A. a skeptic B. an idealist C. a rationalist D. a realist
Berkeley s own views are no less problematic than Locke s because they seem to imply that A. God does not exist. B. The external world does not exist in the absence of sentient beings. C. Primary and secondary qualities are both purely physical in nature.
Idealism vs. Realism Berkeley, as we have already noted, is an idealist. He believes that there is literally no such thing as a physical world existing apart from our idea of it. Locke, by contrast, is a realist. A realist is someone who believes that the world does exist independently of our (or any other being s) idea of it. For review: Regarding the nature of knowledge, the two main classifications are: rationalism vs. empiricism. Regarding the nature of reality, the two main classifications are: realism vs. idealism.
A table Realist Idealist Rationalist Descartes Leibniz Empiricist Locke Berkeley
Hume You may have noticed that neither Kant nor Hume are on the preceding table. Hume is definitely an empiricist, but he can not be classified as either a realist or an idealist in any simple sense. In some ways Hume is a metaphysical skeptic, meaning that he does not think it is ultimately possible to have knowledge of an independent, or transcendent reality. In other ways Hume is a pragmatic realist, because he thinks that it is still perfectly reasonable to treat science as a source of reliable knowledge for practical purposes.
Kant 1 Kant is also difficult to classify because in many ways he is trying to solve the problem that arises from accepting the traditional categories. Traditionally, both the rationalist and the empiricist agree that is possible to have knowledge of an independent reality. They disagreed only on whether reason or experience was the ultimate foundation for such knowledge.
Kant 2 But Kant thought Berkeley had established that knowledge of a truly independent reality is incoherent. When we talk about reality as it is in-itself, we mean as it is independent of any particular conception of it. And it simply makes no sense to speak of our conception of an unconceptualized reality.
Kant with Berkeley s claim that ideas can not resemble an independent reality. A. agreed B. disagreed
Kant 3 But Kant rejected the subjective idealism that seems to result from Berkeley s critique of Locke. Subjective idealism is the view that the world is constituted by ideas alone. Kant thought this view was manifestly false. Kant thought it was clear that there is something corresponding to objective knowledge of the world, a kind of knowledge that independently existing people were capable of sharing. But he needed to articulate the concept of objective knowledge in such a way that he did not fall victim to Locke s apparently incoherent transcendental realism (the view that our true ideas match or resemble a transcendent reality.)
Hume 1 You may recall that Hume had argued that there are only two kinds of truths. analytic truths true by definition, or by virtue of the meanings of the terms alone. e.g., Parallel lines never meet. Circles have no corners. It ain t over till it s over 2 + 3 < 7 synthetic truths true by virtue of the way the world is. Bob is hungry. The earth orbits the sun. There are three chickens on the porch. E=mc 2
Hume 2 Hume had also claimed that Analytic truths are simply relations of ideas, and therefore can be known a priori, on the basis of reason alone. Synthetic truths, being about the world, could only be known a posteriori, or on the basis of experience. Hume had argued that rationalists like Descartes had made a serious error in trying to deduce substantial truths about an independent reality on the basis of reason alone. Kant agreed with Hume, and he thought this mistake was just as serious, involving the same degree of incoherence as Locke s mistake of identifying ideas that resembled an unconceptualized reality.
Hume 3 However, while Kant mostly agreed with Hume s skepticism about the nature of an independently existing reality, he still thought reason could teach us quite a bit more than Hume allowed. Hence, Kant also desired to avoid the skepticism, or merely pragmatic realism of Hume.
Kant s task So Kant s task was to try to develop a view that avoided. Berkeley s subjective idealism. which denied an objective reality altogether. Locke s transcendental realism. which was properly criticized by Berkeley as incoherent. Descartes rationalism which was properly criticized by Hume as incoherent. Hume s skepticism which did not fully credit the power of human rationality.
Kant s approach As Adrian Moore explained in the interview, Kant identified a kind of truth that he believed Hume and others had overlooked. Hume had said that analytic truths were known a priori. synthetic truths were a posteriori. But Kant made the surprising claim that there could be synthetic truths that could be known a priori.
Synthetic a priori truths Synthetic a priori truths are necessary truths about the world itself. They are not simply true by definition. They are not based on experience. Some examples of synthetic a priori truths are: Two objects can t be in the same place at the same time. An object can t be completely red and completely green. Time doesn t flow backwards. Causes determine their effects. There are three spatial dimensions. Again, the distinctive quality of these statements is that they seem necessarily true, but also seem to be about the world in a way that analytic truths are not.
Another table A priori A posteriori Analytic There are 60 seconds in a minute. Synthetic Time does not flow backwards. The final exam lasts 2 hours
How are synthetic a priori truths possible? For Kant, then, the key question is: How are synthetic a priori truths possible? His answer is that synthetic a priori truths are not about an external reality at all, but about the conditions of experience itself.
The key move in Kant s metaphysics is to explain how A. subjective idealism is possible. B. synthetic a priori truths are possible. C. transcendental realism is possible. D. empirical a posteriori truths are possible.
What does that mean? To see what this means, think about a concept like space. We are accustomed to thinking of space as something that is external to us, in the sense of being part of reality itself. Kant, however would say that space is not part of reality itself, but the form in which reality is presented to us. He says the same thing about other fundamental concepts like time, causation, and mathematical and geometrical relations.
The Lockean picture So, whereas Locke saw the world in terms of our ideas either resembling or not resembling reality, like this: Ideas Reality Shape is a primary quality that matches reality, color a secondary quality that does not.
The Kantian picture Kant saw reality as being filtered through a kind of grid, the necessary forms of experience, that everyone shares in common. Subjective reality or inner experience Empirical Reality or outer experience Transcendent Reality? Forms of experience
The Kantian picture On the Kantian picture, there is a transcendent reality about which we can know nothing except that it exists. Reality is conditioned by the forms of experience, the nature of which can be known on the basis of reason alone. Subjective reality or inner experience Empirical teality or outer experience Transcendent Reality? Forms of experience
For Kant, the only thing we can know about transcendent reality is that A. it is a form of experience. B. it is conditioned by the forms of experience. C. it resembles our outer experience. D. it matches our inner experience.
The Kantian picture Empirical reality is what science studies, and it corresponds roughly to Locke s primary qualities. Importantly, however, it is not independent of experience; it has been filtered through the forms of experience. It is objective, however, in the sense that everyone shares the same grid. Locke s secondary qualities remain subjective. Subjective reality or inner experience Empirical reality or outer experience Transcendent Reality? Forms of experience
The Kantian picture Note that on Kant s scheme we can now make sense of the question whether our idea of a circle resembles empirical reality, because empirical reality is not independent reality. It is already conceptualized. Subjective reality or Inner experience Empirical reality or Outer Experience Transcendent Reality? Forms of experience
Was Kant right? Kant s view of the world was very powerful, and there is no question that it helped to articulate the foundations of what we now call cognitive science. It is now well-established that our mind is not a blank slate at birth, but imposes a certain structure on the world. However, Kant was probably not correct in thinking that the forms of experience could be determined by reason alone, or that they constrained inquiry quite as rigidly as Kant believed. For example, Kant believed that science was constrained to conceive of space as 3-dimensional and causality as deterministic. But neither of these has turned out to be true. Hence, there may still be some coherent sense in which the purely mathematical models of science are describing a transcendental reality.