First several misunderstandings are discussed in §1 . Then in §2 the model will be presented. It will be useful for the understanding of the description of the phenomenological data described in §3,4. In §3 mystical and other experiences are described that are obtained during the path of mental purification. In §4 the account of this training will be continued, but no longer focused on existentialist experiences. It turns out that there is something better than mysticism: freedom. Finally in §5 a program is sketched for scientific verification of the reported phenomena and other statements.

The model is based on experience obtained during several intensive vipassana meditation retreats (more than 90 days over a period of 7 years, after several preparatory years of so called concentration meditation). The motivation for such a training is twofold. First of all, the purpose of the training is inner calm and freedom, in themselves of enough value. Secondly, part of the training consists of an introspective study of consciousness. Thereby one obtains insight in the functioning of the mind, complementary to information obtained in disciplines such as neurophysiology and cognitive science.

Introduction This paper is an elaboration of a lecture given at the University of Delft (October 2, 1992) for the symposium Over grenzen (On boundaries); a preliminary version (in Dutch) is in Vlug [1993]. A model will be presented for the human mind in which mysticism plays a clear role. Moreover, the model discusses also the cause of human suffering and desire and our possible liberation from it.

This paper continues the description of experiences obtained during the practice of intensive vipassana meditation. Moreover, based on these experiences a model is presented for one particular aspect of the human mind: the mechanism of desire, suffering, mysticism and mental purification. The model makes very clear the goal of the meditation training and explains well the phenomena described in the Buddhist literature. Besides that the model is claimed to be useful for the understanding of several psychosomatic phenomena.

Most human beings use the external method for their happiness. The method of internal control is important for the purification of our consciousness. However, when the path is completed, there is no difference between the two methods anymore. Both will be seen as tiresome manipulations. Moreover, in that state of buddhahood there will be no longer need for either form of control. Also this almost paradoxical aspect will be explained by the model in the next section.

The method to perform this change in our consciousness is called the path of purification. Perhaps this path does not appeal to you; perhaps it does. In any case, the information obtained this way is important for the understanding of the human mind.

Applied science allows us to make our surroundings more pleasant to live in. This is in accordance with the first method of external control. However, as mentioned before, control has its limits (scientific, political, ecological and financial). Therefore it is good to know also another method to solve our suffering. This consists of an internal modification of our consciousness in such a way that the situation in which we are is no longer perceived as unpleasant. In order to do so an essential change in the way our mind functions is necessary. What kind of change this is will become clear by the model of our mind given in the next section.

In the same way most people are involved in controlling their circumstances in order to have happiness. Because our capacity to control has its natural limitations, in this way there will always be resulting suffering. Later we see that there is a better way. The possibility of insight in the functioning of our mind and the resulting spin off towards the lessening and eventually stopping of our suffering is the main basis for the existence of Buddhism. These will be explained by a model in §2 . Internal-external This pair of opposites can be approached also by the words subject-object. The following is meant. Suppose we are in an unpleasant situation. Then there are essentially two different ways to try to do something about the resulting suffering: 1. to change the situation itself (external); 2. to change our consciousness of that situation, so that it is no longer perceived as unpleasant (internal).

Unfortunately it is the case that the public opinion and therefore also the politicians see the capacity to control as the main motivation to do science. Therefore science has to be defended by short term successes in its applications. The aim to obtain insight thereby becomes somewhat neglected.

With this understanding we may obtain considerable control of the situation around and inside us. This results in the second motivation for science. We want to be able to control things. And indeed we are reasonably able to do this as a spin-off from our obtained insight. We can go to the moon; we can program a bacteria to produce human insulin. These are impressive examples.

The difference between the quest for control or insight can also be seen in the motivations to do science. Originally science is motivated by our strong curiosity, which is the quest for insight. We want to understand the phenomena around us. Now what exactly is insight, understanding? An absolute answer why things behave the way they do cannot be given. This is known already by children that have discovered that after every answer given to them they can ask again `Why?'. Insight consists of a simplification of the situation. It consists of knowledge about parts of the situation from which properties of the situation itself can be derived. This was already discussed when we dealt with reductionism. We understand how and why the planets make a loop-shaped movement between the fixed stars. We understand what is the chemical basis of heredity.

Proper opposites In the discussion about spirituality it is good to emphasize two genuine opposites: control-insight and internal-external. Control-insight This pair of opposites indicates two fundamentally different attitudes towards life. Very often we want to control circumstances in and around us. This is for good reasons: these circumstances determine our well-being, our degree of happiness. However, once we have enough to eat and live relatively comfortable, our desire to control may expand and makes us want things that are beyond our capacity. This results in suffering, because there will be things that we want that are outside our reach. Insight on the other hand also gives us pleasure but one that is more permanent. For the pleasure of eating a cake we must pay by not having it any more. The pleasure of understanding the theorem of Pythagoras will remain inside us and can be revived as soon as we care to think about it.

Having a free will means that we can make a decision based on a considerations involving among other things our thinking and feeling. Being determined means that those considerations follow a fixed path. But the only way to know the outcome of those considerations and thereby of that decision is to live and go through the process. The outcome is of interest because even if it was determined, it was unknown before. Compare this to a computer that calculates the number pi in 10 6 digits. The digits are determined before the computation starts, but nevertheless the computation has to be done.

The reader may feel uneasy about this. That is so for good reasons. The fact that we may have a free will and are at the same time completely determined is related to a fundamental characteristic of our existence: we are selfless. We have no absolute control over what happens in our mind. Says Saint Augustine: If my mind orders my body to do something, then my body obeys so well, that one can hardly distinguish between the order and its execution. If, however, my mind orders my mind to do something, then it does not listen, even if it is the same mind. Why this monstrous phenomenon and for what purpose? Schopenhauer says something related: We are able to want to do something, but we cannot [force ourselves to] want to want something.

Still one may object. In some views on a human free will - e.g. the one propagated in Christianity - there is an (eternal) soul that independently makes decisions. In this sense the second chess computer does not have a free will, since its behavior is exactly determined by the position on the board and by its past experience. But a really independent soul that makes decisions that are not based on anything is in fact being haphazard, is a random generator. This is not what is meant by free will - even in Christianity. According to this religion one should base one's actions on the dictates of one's conscience (taking into account the circumstances). Doing this, however, our behavior is comparable with that of a chess computer of the second kind, albeit that we are much more refined.

The following example may be useful. Imagine we have a chess computer, a cheap one that always uses the same strategy. Now if playing against it we win a game, then we always can win by repeating our successful strategy. It is clear that this machine is deterministic and does not have a free will. Now imagine that we have a more expensive chess computer, one that learns from its mistakes. After winning from it in a game, we cannot win again with our previous strategy. The machine will remember that it is not good to repeat its moves. We can state that this second machine has a rudimentary form of a free will: it reacts differently under similar circumstances. But since the machine is programmed its behavior is deterministic. So determinism and free will are compatible.

The matter is, however, much more simple. In the philosophical struggle in which one tries to choose between determinism or free will it is assumed that the two are mutually exclusive. This is not correct. The reader may try to give a careful argument that determinism implies that there is no free will; this attempt will be in vain. The reason is that determinism means not only that things are completely determined but also that this is so by a cause, by nature. Well, we are part of nature and therefore our presence and our behavior is of genuine influence on the course of things.

One has invented many ingenious arguments to try to give a solution. Quantum mechanics seemed to be reassuring. Nature is apparently not deterministic, according to some interpretations of this theory, and thereby the human dignity is saved. To this one may make the following objections. First of all this solution is not satisfactory, because in this way our behavior is based on stochastics, on the throwing of a die - not very dignified indeed. Moreover in spite of the phenomena described in quantum physics, determinism is not ruled out in principle. The often cited experiment of Aspect based on a theorem of Bell is sometimes seen as a proof that determinism is impossible, see Aspect [1982]. But although the experiment is very interesting, it does not lead unambiguously to this conclusion.

As conclusion I want to state that reductionism and holism do not contradict each other. On the contrary, they can complement each other fruitfully. Determinism-free will It is noteworthy that in the history of human thought this pseudo-discrepancy has been three times the cause of intensive polemics. This happened in fundamental discussions in theology, in classical physics and more recently in artificial intelligence. The main idea is simple. Nature, including homo sapiens, is completely determined according to some theories. This for different reasons depending on the particular school of thought. According to some theological views God completely determines the world. According to classical physics the laws of nature and the state of the universe at a given moment completely determine the future. Now, if the world is completely determined what about our free will? It seems at least that we have one. In artificial intelligence, in which man is considered as an information processing system, the question comes up in an analogous way.

Holism may be defended as follows. If one has not yet succeeded to select in a given setting the proper components together with a successful description of these, then a more global approach is the only possibility. In this situation reductionism is a working hypothesis, a scientific program. Moreover, even if the reductionist analysis of a situation happens to be completed successfully, it is still important to pay attention to the total. As comparison one may think of the performance of a piece of music. First one has to practise the difficult passages (reductionism). Thereafter these passages and the other parts should be integrated into a balanced total (holism).

Holism on the other hand emphasizes that one should not neglect the global view. `The whole is more than the sum of its parts' is one of the slogans of holism. As pointed out by Nagel [1961], the truth of this statement depends on the way the concept `sum' is interpreted. If one has an amplifier, a cd-player, speakers and wires, than one does not yet have a working stereo-set. The parts have to be connected in the correct way by using the wires. If in the interpretation of the concept `sum' this correct wiring is included, then the total is the sum of its parts. A holist may maintain that with a stereo-set one can listen to cd's, something that is not possible with any of the parts. This is correct, but should be stated as `the properties of the whole are not the sum of the properties of the parts'. The aim of reductionism is to describe the properties of a whole as a function (not a mere addition) of the properties of the parts. Usually the total has extra properties (that is why we make compound objects). It may also happen that properties of the parts are lost after the total is formed (e.g. iron Fe is susceptible to rust, but iron-oxide Fe O 2 is not; sodium Na and chlorine Cl are poisonous but NaCl, table salt, is not).

In conclusion, mysticism and rationality are not incompatible. Both are based on a refinement of the human mind, albeit in somewhat different directions. It is important that rationality is not confused with bureaucracy and mysticism not with mystification. Reductionism-holism Reductionism is the method that tries to understand the behavior of certain objects in terms of their components. In this way science has achieved great successes. By selecting in a situation the right components whose behavior can be described and be used in a description of the behavior of the total situation, one has obtained a good understanding of many phenomena in nature.

So much for the allergy of rationalists against mysticism. As to the converse - the allergy of a mystic against rational thought - it can be said that again there is a misunderstanding caused by a difference in motivation. The mystical training is directed towards a cultivation of introspection as a refined instrument. This introspection should not be distorted by projections and the like. Often rational thinking acts as a disturbance for proper perception of phenomenological experience. Therefore one has to be careful with rational thought during the purification of consciousness. It is sufficient to be always aware of our thinking or reasoning whenever present - however, that is not so easy.

A rationalist may object that even if the statements of a mystic may not be impossible, there is no logical ground for them. This objection may be refuted by pointing out that the statements of a mystic are empirical, based on experience in a trained consciousness. Nevertheless it would be good if a mystic would state clearly that he or she is speaking about internal experience.

The following example - already given in part I - may be explanatory. Suppose there is an island with inhabitants that are able to see only the colors black and white. In their `logic' one has the following law: `something is either white or black'. In the language on the island the word for `black' is `non-white'. Hence this law can be formulated as: `something is either white or non-white'. Now someone on the island has the mystical experience that we know as seeing the color green. The mystic may say: `I have seen something; it was neither white nor non-white (and it was splendid)'. According to the logic of the island this is a contradiction. But we know better.

Nevertheless this pair is only apparently in opposition. In Staal [1975] the following is stated: `Mysticism consist of experience. As such it is neither rational nor irrational; but this experience can be studied in a rational way'. Paradoxical statements may be made understandable, if we realize that using common language uncommon experience has to be described.

Improper opposites Rationalism-mysticism This seems to be a proper opposite. A rationalist only makes statements if these are based on logical thought. In mysticism this is not the case; sometimes even some contradictory statements are made. Conversely, in mysticism one is warned against the influence of rational thinking.