Scientific exploration and thus our knowledge about the outside world is subject to the conditions of our experience. These conditions are condensed here into an interface model which, besides being physical, has an additional interface structure not reducible to physics. We suggest that this structure can dynamically be characterized by separate modes. Their selection and operation presupposes free will and a rudimentary concept of time and space. Based on some analogies with quantum networks it is argued that the "observed" gets "dressed" as a consequence of the observing. Interface dynamics and system dynamics supplement each other without over-determination.

A non-classical logic is proposed that extends classical logic and set theory as conservatively as possible with respect to three domains: (i) the logic of natural language, (ii) the logcal foundations of mathematics, and (iii) the logical-philosophical paradoxes. A universal mechanics of consciousness connects these domains, and its best witness is the liar paradox. Its solution rests formally on a subject-object partition, mentally arising and disappearing perpetually. All deep paradoxes are paradoxes of consciousness. There are two kinds, solvable ones and unsolvable ones. The solvable ones disappear by proper partitions, the unsolvable ones arise by inevitably improper partitions enforced by the natural worldview. The categorial distinctions of subject and object, certainty and truth, consciousness and being, inner freedom and outer constraint, psyche and physis, mental practice and formal theory indicate an immemorial mystical monism of consciousness without which mathematical Platonism could not survive.

Similar problems keep reappearing in both the discussion about the "hard" problem of consciousness and in fundamental issues in quantum theory. We argue that the similarities are due to common problems within the conceptual foundations of both fields. In quantum physics, the state reduction marks the "coming into being" of a new aspect of reality for which no causal explanation is available. Likewise, the self-referential nature of consciousness constitutes a "coming into being" of a new quality which goes beyond a fully causal account of reality. Both subjects require a categorical scheme which is significantly richer then the one used in addressing factual aspects of reality alone. While parts of this categorical scheme are realized in the formalism of quantum theory, they are seldom applied in the context of consciousness. We show what the structural limitations of a classical categorical framework are, how a richer framework can be developed, and how it can be applied to both quantum physics and consciousness.

Computationalism is the claim that all possible thoughts are computations, i.e. executions of algorithms. The aim of the paper is to show that if intentionality is semantically clear, in a way defined in the paper, then computationalism must be false. Using a convenient version of the phenomenological relation of intentionality and a diagonalization device inspired by Thomson's theorem of 1962, we show there exists a thought that cannot be a computation.

In the hard determinism of Newtonian physics all aspects of the universe are deterministic and therefore all future behavior in the universe is determined by its present state. Hard determinism is incompatible with the existence of free will, but not with the belief in the existence of free will. It is analyzed what is required from physics for free will to exist. It is detailed which conditions must be fulfilled for randomness to be sufficient for the existence of free will, and it is argued that these conditions are valid in our physical universe. The approach to physics that is used is Zurek's information-based interpretation of measurement in quantum mechanics, called quantum existentialism. Zurek's approach is capable of describing the boundary between quantum physics and Newtonian physics in great detail. Belief in hard determinism increases the chances of feeling hopeless, and thus a direct consequence of the belief in hard determinism is a reduction of emotional well-being. The results obtained imply that the belief in the existence of free will is compatible with observed reality.