**1. Introduction**

In an interview for "New Scientist" in February 2011, biological novelist Christian de Duve stated that the cost of human success on earth is the exhaustion of natural resources, leading to energy crises, climate change, pollution and the destruction of our habitat. If we continue in the same direction, humankind is heading for some frightful ordeals, if not extinction. He believes an inherent selfishness in human nature is responsible for this behaviour passed on through human genes. [1]

This somewhat fatalistic statement raises an old philosophical question: are human beings able to act according to free will or are they pre-determined—pre-programmed—by the physical state of their brain, which is based on their genetic traits.

First of all, the set-up, results, and two main conclusions of the famous Libet-experiment [2] have to be described in order to be able to shed light on the context of the thought-experiment:

The set-up of the experiment involves EEGs being attached to subjects' brains, monitoring when their brains indicate a decision is made and comparing this to when subjects indicate being aware of having made a decision. The results show that the pre-conscious brain indicates a reliably predictive "readiness potential" signal approximately 0.33 s prior to test subjects reporting an awareness of having made a decision on their own. The two main interpretations are:

• First, as the readiness potential reliably predicts the subsequent decision, Libet concluded that the brain has decided prior to having become aware of consciously making a decision. This implies that the conscious awareness of having made a decision is an epiphenomenon, which undermines the free will notion that volition is informed by conscious election.

• Second, Libet was nonetheless of the opinion that this study does not rule out the possibility that individuals retain a "veto" option, that is to say they can override what the brain delivers, if they so choose, and veto the brain's decision just prior to the moment of enacting it.

More recent work has established, first, that when test subjects were asked to press either a left-hand or right-hand lever, analyses of their brain states reliably predicted which hand would be chosen up to six seconds prior. Secondly, the readiness potential itself has been debunked as a sort of mathematical noise of the equations used to measure brain activity.

This paper links its interpretation of the thought experiment with Libet's assertion that the conscious agen<sup>t</sup> retains a veto power. We shall assume test subjects would wish to falsify such a prediction every now and then, supporting the existence of free human will.

#### **2. A Thought-Experiment in Favour of Free Human Will**

In preliminary matters, we need one axiom:

A system is considered to be determinate, as long as its state and therefore resulting future can in principle be known in advance. For the following thoughts, it is sufficient if the state and the further dynamic development of the system can be known at least two seconds or more into the future.

We start with the system in Figure 1. The system consists of the following elements:


**Figure 1.** A system consisting of a human who has to decide whether to drink a cup of pure water (A) or one of wine (B). Only the brain and eye of the human being is sketched. The brain of the human is fully detected; its state of being is represented on a screen. If the way the human brain works is predetermined, the observer will know in advance if the human will choose possibility A or B.

The whole system in Figure 1 is considered to be pre-determined, a classical physical system without in-deterministic influences. The brain of the human being produces electrochemical results which "somehow" are related to subjective perception. Instantaneously, the whole objective system of the "brain" with all its signals is detected by a probe, interpreted by a computer and is displayed to an observer. The "somehow"-production of subjective impressions as well as the details of the detecting probe and the representation of the state of the brain, are not the focus of this paper.

The observer can, as a consequence of detection, interpretation and representation, know in advance what the electrochemical system "brain" intends to do, when its subjective correlate, the human consciousness, is confronted with a simple decision. The human has to decide between two options with almost the same level of priority, meaning that both are more or less equal for them. In our example, the human has to decide whether to drink from cup A which contains pure water, or from cup B which contains red wine. This is also the principal idea of Libet's experiment.

The system "brain" is a determined physical/chemical/biological system, as are the rest of all elements in Figure 1. In Figure 1, the brain would make the decision prior to the human's subjective perception where it actively decides between possibilities A and B. Therefore, the observer would know: "you decide to choose option A" and the human would follow. Everything remains in the predetermined world.

Now, let us change the situation in Figure 1 slightly to that in Figure 2.

**Figure 2.** This is the same system as in Figure 1, except for one di fference: now the human actor who has to decide whether to take cup A or B can simultaneously watch a screen which would represent to himself/herself the inner state of his/her brain. The human actor would know at least about two seconds in advance which of the two possibilities, A or B, his/her brain would select. Due to his/her consciousness, however, the human actor is now able to refute any predetermined decision of his/her brain.

We turn the screen representing the inner "physical" state of the human brain around so that the eye of the human being, the brain—which is being detected and observed—is able to watch it (Figure 2). Again, the whole system, as a hypothesis, is considered to be determined.

In this case the human being—again sketched as a brain and eye in Figure 2—would learn about two seconds in advance which decision it is about to choose (A in our example). This again happens prior to the human's subjective perception that it has actively decided between possibilities A and B. Is the human being now obliged to choose alternative A, as the representation of the inner physical state of his/her brain tells them via the screen that it is about to choose alternative A? Definitely not.

In Figure 2 there is unquestionably something placed in the system which is able to refute any forecast of the deterministic system. Whenever the chain along brain-detection-representation and observation (b-d-r-o) mirrors a certain result, something in between is able to prove that this very result can also be di fferent.

This "something in between" is the free, resistive will (libero arbitrio). The hypothesis represented in Figure 2, that the whole system is a pre-determined system, is disproved.

It is important to keep the following in mind:

