Concepts behind the displays
These are ideas that are implicit in the displays, but usually not discussed directly. A goal of the Explanade as an experiment in communication is to reduce these concepts to common language and experience. The list below is also a description of what I believe, and that gets implicitly woven into everything I say. It would be dishonest to pretend otherwise.

Reductionism vs. Holism
Reductionism and holism are tools for understanding complex entities. In reductionism, one takes a thing apart into smaller elements, studies those, and then conceptually assembles the elements back into a whole to predict its behavior (a “bottom-up” approach). One does this because understanding the whole is too hard. In holism, one considers the whole entity as a system that operates together, and one tries to understand the big picture (a “top-down” approach). These are appropriate in different contexts, or maybe used simultaneously. Causality can go in either direction (top to bottom or the reverse).

It is also possible to misuse either of these approaches when the opposite one would be more appropriate. Holism is harder to theorize, and so is new compared with reductionism, which has been the more often used scientific technique.

Empiricism vs. Rationalism
Empiricism is the idea that knowledge comes ultimately from experience. Experience trumps theory, if they conflict. Rationalism is the idea that knowledge comes ultimately from pure reason, which would trump experience if they were to conflict. Science is empirical. It works better. Rational theorizing can lead to many dead ends that fail “when the rubber hits the road.”

Realism vs. Idealism vs. Instrumentalism
Realism is the idea that things exist (in the physical world) independent of our minds. We form theories to describe things that we discover, which existed before we knew them. A theory describes the “real world.”

Idealism is the idea that nothing exists independent of our minds. Theories create reality rather than describe it. The mind-independent world is an illusion we invent.

Instrumentalism is the idea that physical theories are just instruments to predict experimental results or the performance of a new gadget, and do not describe ultimate reality. Theories input things you have observed and output predictions of things you will observe. In this view, it makes no sense to talk about unobservables, like the existence or non-existence of reality outside our minds. Science is about what you know, not about ultimate truth.

It is possible to form a position that synthesizes both instrumentalism and realism. Idealism, though, is antithetical to science, since it results in the conclusion that the laws of nature are in some sense arbitrary. We do not find this to be the case.

Materialism vs. Idealism vs. Dualism
Materialism is the idea that the mind is made of matter, with the brain the likely place for its seat. Idealism is the idea that matter is made of mind, created by consciousness. Dualism is the idea that the mind exists as a supernatural entity outside matter, but which somehow causes matter to move.

Scientists are typically materialists, because one assumes at the outset that there is nothing supernatural. Everything can be explained in terms of the action of matter, somehow. Even the position that the mind is an “emergent property” of matter (see below) allows the mind to be treated special while consisting ultimately of matter.

The philosophy of mind is only mentioned briefly in the Explanade. It is necessary to discuss because empirical knowledge is the interaction of mind with the physical world. The relation of the mind to the physical world has to be mentioned.

Emergence and Self-organization
Emergence is the idea that a complex system consisting of many interlinked simple elements can exhibit behavior that is not encoded into the elements themselves, but is the result of their being interlinked. Examples include the mind emerging from nets of neurons, or life emerging from connected molecules, or atoms and molecules emerging from subatomic particles. Self-organization is the tendency for many simple elements to form long range ordered systems when they interact. Both of these phenomena can explain “ghost in the machine” or “intelligent design” observations, making smart spirits unnecessary.

The characteristics of the everyday world emerge from arrays of quantum particles, partially explaining the mysteries of “quantum weirdness” versus what we are familiar with. Maybe even the apparent forward flow of time is an emergent property of masses of timeless quantum particles.

Scientific Method
There is a way to know the physical world which works better than any previous method. It is based in experience and testing theory against observation. It works like this:
See something you don’t understand.
Take a guess as to why it is that way.
Set up a special observation to test your guess.
Compare the guess with the observation.
Change the guess if it doesn’t predict the observation.

Since using this method, humanity has advanced far beyond previous attempts in knowledge and technology. The method is based on certain choices of knowledge and existence theories. Individual scientists don’t work according to this list of steps, but the scientific community as a whole does. It becomes confusing when many people are doing different steps of the method simultaneously, and sometimes jumping back and forth between steps, but the thread of the logic and motivation of their work is this method.

Uncertainty
Uncertainty is inherent in knowledge gained through experience. We cannot have omniscience, so we can only experience a small fraction of what exists, and generalize from that. We may be wrong in our generalizations, and so are uncertain about them. We use our experience to predict what will happen, but we cannot know the future for certain, so we are uncertain of our generalizations from past experience to future. Further, there are some things we cannot know to arbitrary precision, since they are inherently random or irreducible. Thus there is uncertainty throughout science.

Yet, the knowledge and predictions of science are more reliable than any other human knowledge of the physical world. We happily bet our lives on it almost daily. Science gives us a good bet, in fact the best, and that’s all we need.

Epistemology and Metaphysics
Epistemology is the study of knowledge and truth. Metaphysics is the study of what exists and what doesn’t (in general), and what it means to exist at all. They are intimately related, because our ability to know the world depends on what’s there, and what we are. Given some idea of what exists, we can determine how we can know it, and what is the nature of our knowledge.

“Truth” and “Reality” are not popular concepts in the postmodernist humanities right now, part of why those fields are at war with science. A major goal of the Explanade is to show that choices of epistemological and metaphysical positions determine many other practical choices, whether we make our philosophical choices consciously or not. Usually, we just accept the implicit choices of those around us. This may be a mistake.