On April 3th, Professor Leo K. C. Cheung (张锦青）presented the lecture “The Metaphysics of Wittgenstein’s Tractatus” for students and faculty members of the School of Philosophy. Prof. Cheung is from the Department of Philosophy, Chinese University of Hong Kong. He is also the dean of the department.

(Prof. Cheung)

Prof. Cheung argued that the Tractarian ontology is derived from and based on the insight Wittgenstein generalizes from Hertz’s, and discussed several important implications of the Tractarian ontology. According to Prof. Cheung, Heinrich Hertz’s important insight concerning any adequate theoretical language of physics can be eventually expressed as follows: an adequate theoretical language of physics is a complete description of the world of physics. Wittgenstein generalizes Hertz’s insight to the case of language in general, and an immediate corollary of his main point can be expressed as follows: it is possible to establish an adequate symbolism showing that the world can be described completely by propositions of the adequate symbolism.

Prof. Cheung also argued that there are five implications of Wittgenstein’s generalization.The first implication is that there can be different indiscernibles. The second implication is that there are two different ways of describing the Tractarian world completely. The third implication follows from the second, that transworld individuation of objects is impossible. Fourth, Tractarian objects obey Bose-Einstein statistics, that is, a quantum statistics. Fifth, by taking quantum particles to be Tractarian objects, the Tractarian ontology suggests a way of labeling quantum particles. This, to a certain extent, may contribute to resolving a puzzle concerning whether quantum particles are individuals.

In the last section of the event, Prof. Cheung answered and responded to several questions and criticisms raised by the audience. （Written by Niu Yao, Photo by Liu Xu）