Customary interpretations state that Tractarian thoughts are pictures, and, a fortiori, facts. I argue that important difficulties are unavoidable if we assume this standard view, and I propose a reading of the concept taking advantage of an analogy that Wittgenstein introduces, namely, the analogy between thoughts and projective geometry. I claim that thoughts should be understood neither as pictures nor as facts, but as acts of geometric projection in logical space. The interpretation I propose thus removes the root of the (...) identified difficulties. Moreover, it allows important clarification concerning some central aspects of the Tractarian theory of representation, and it yields a unifying elucidation regarding Wittgenstein’s remarks on the solipsistic thesis. (shrink)

In this paper, I aim to shed light on the use of transcendental deductions, within demonstrations of aspects of Wittgenstein's early semantics, metaphysics, and philosophy of mathematics. I focus on two crucial claims introduced by Wittgenstein within these transcendental deductions, each identified in conversation with Desmond Lee in 1930-31. Specifically, the claims are of the logical independence of elementary propositions, and that infinity is a number. I show how these two, crucial claims are both demonstrated and subsequently deployed by Wittgenstein (...) within a series of transcendental deductions, a series which begins with extensionalism as a generalized condition of sense on propositions, and in the context of which are then derived various, further, significant and unobvious presuppositions generated by that generalized condition of sense. In addition to clearing up deductions of these two, aforementioned claims, I also elucidate deductions of the subsistence of objects, and of logical space as an infinite totality. (shrink)

This book attempts to explicate and expand upon Frank Ramsey's notion of the realistic spirit. In so doing, it provides a systematic reading of his work, and demonstrates the extent of Ramsey's genius as evinced by both his responses to the Tractatus Logico-Philosophicus , and the impact he had on Wittgenstein's later philosophical insights.

This paper is both systematic and historical in nature. From a historical viewpoint, I aim to show that to establish Wittgenstein’s claim that “an ‘inner process’ stands in need of outward criteria” there is an enthymeme in Wittgenstein’s private language argument overlooked in the literature, namely Wittgenstein’s suggestion that both perceptual and bodily experiences are _transparent_ in the relevant sense that one cannot point to a mental state and wonder “What is that?” From a systematic viewpoint, I aim to show (...) that Wittgenstein’s PLA teaches us that the prevailing picture of the nature of phenomenal concepts is upside down: we can only introspectively know what is going on inside our heads, after we learn of what is going on outside. In this regard, I aim to defend two associate claims against the prevailing view of PCs on the basis of PLA. First, by means of transparency, I aim to show that there is no _de re_ awareness of our private sensation that could determine the meaning of sensation-words; for example, I am never aware _of _the phenomenal blueness of my experience of something blue. The second associated claim is that introspective self-knowledge of our private sensation is always _de dicto_. We can only know introspectively that phenomenal blueness is the phenomenal character of the experience we are undergoing after we have learned _that _ blue is the color that usually causes in us that kind of experience. Likewise, we can only introspectively know that pain is the phenomenal character of the experience we are undergoing after we have learned that pain is what usually causes some typical pain behavior. (shrink)

This book brings together philosophers, mathematicians and logicians to penetrate important problems in the philosophy and foundations of mathematics. In philosophy, one has been concerned with the opposition between constructivism and classical mathematics and the different ontological and epistemological views that are reflected in this opposition. The dominant foundational framework for current mathematics is classical logic and set theory with the axiom of choice. This framework is, however, laden with philosophical difficulties. One important alternative foundational programme that is actively pursued (...) today is predicativistic constructivism based on Martin-Löf type theory. Associated philosophical foundations are meaning theories in the tradition of Wittgenstein, Dummett, Prawitz and Martin-Löf. What is the relation between proof-theoretical semantics in the tradition of Gentzen, Prawitz, and Martin-Löf and Wittgensteinian or other accounts of meaning-as-use? What can proof-theoretical analyses tell us about the scope and limits of constructive and predicative mathematics? (shrink)

Bertrand Russell dedicó parte de su obra a la discusión sobre el problema de la referencia y la descripción . Russell, junto Whitehead, elaboró un tratado de lógica matemática, titulado Principia Mathematica en el que retomó el proyecto de Frege tratando de demostrar que la matemática es una rama de la lógica. Russell no sólo tiene este propósito logicista, sino que también quiere concebir un lenguaje lógicamente perfecto , esto es, un lenguaje preciso, en el que se elimina toda ambigüedad (...) y vaguedad. En una palabra, el lenguaje de la ciencia en el que a todo nombre, por ejemplo, le “corresponde” un objeto. El Wittgenstein de las Investigaciones filosóficas se enfrentará a tal proyecto y a la concepción de un lenguaje cartográfico de la realidad. El autor, propone por el contrario, la reivindicación de un lenguaje sencillo, austero, cotidiano y plural, lejos de toda “estructura oculta”, finalmente, un lenguaje que no trasgreda las prácticas comunes y de paso a un lenguaje filosófico menos “enredado” y “dogmatico”. Pretendemos resaltar cómo la crítica a la búsqueda de un lenguaje perfecto permite que al lenguaje y a la filosofía misma, se les conciba de un modo más abierto, cotidiano y plural, en palabras del mismo Wittgenstein, una filosofía descansada “que ya no se fustigue más con preguntas que la ponen a ella misma en cuestión”. (shrink)