What we have written about the nature of evil thoughts also shows their causes. According to St. Gregory of Sinai, the origin and cause of evil thoughts lies in "the splitting up, through man's transgression, of his single and simple memory" (398). Before his transgression man's memory was simple, that is, it had no passion and it was turned entirely towards God. All the powers of the soul were centred on God. Immediately after the transgression this single memory was split up. St. Thalassios teaches that evil thoughts arise from three sources: the senses, the memory, and the body's temperament. The worst are those that come from the memory (399).
I think that St. Isaac the Syrian gives us a starting-point for seeing more clearly the causes of evil thoughts and what it is that provokes them. He teaches that "the movement of thoughts in a man originates from four causes. Firstly, from the natural will of the flesh; secondly, from imagination of sensory objects in the world which a man hears and sees; thirdly, from mental predispositions and from the aberrations of the soul; and fourthly, from the assaults of the demons who wage war with us in all the passions. Therefore as long as a person remains in this world he cannot avoid thoughts and warfare" (400).
The basic cause of evil thoughts is the warfare of the devil. The majority of evil thoughts are from the devil. The devil's aim is to lead a man to sin either in thought or in action. He even waged war against Christ Himself, naturally without any success. The demons who are always trying to lay hold of our soul do so "by means of impassioned thoughts" so that they may cause it to sin either in the mind or in action (401). When a man thinks evil, he sins in thought, whereas when he does the will of the devil and gratifies his desire, he sins in action. The committing of sin is called sinning in action. The demons constantly sow thoughts in order to capture the nous. The saints recognise "the seeds of the demons" and advise people accordingly (402).
St. Gregory of Sinai says that thoughts are the words of demons and the forerunners of passions. First comes the thought, and then the sin is committed (403). According to Ilias the Presbyter, demons wage war against our soul first through thoughts and not through things. "Hearing and sight are responsible for the warfare waged through things, habit and the demons for that waged through thoughts" (404). The demons constantly implant impure and shameful thoughts. Each passion has its corresponding demon, and St. John of the Ladder emphasises that shameful and unclean thoughts in the heart come from the deceiving demon of the heart (405). The cunning of the demons in this warfare is great, and only the saints whose nous is pure and who have the gift of insight can distinguish it. Thus St. John of the Ladder writes that he once noticed the demon of vainglory doing a double piece of work. In one brother he sowed thoughts of vainglory, and at the same moment he revealed those thoughts to another brother so that he would be praised as a thought-reader and thus fall into the sin and passion of vainglory (406). Therefore the devil's warfare against us by means of thoughts is harder than that waged by means of material things (407).
But usually the devil takes his opportunity from the passions which exist in our soul in order to launch the appropriate warfare of thoughts. He knows the passions that are there and he excites the soul at those points. "The passions lying hidden in the soul provide the demons with the means of arousing impassioned thoughts in us" (408). And since the most basic passion, from which all the others are engendered is self-love, it is in the passion of self-love that "the three most common forms of desire" have their origin (409). When the heart of man inclines towards self-indulgence, it becomes a source of evil thoughts: "From a pleasure-loving heart arise unhealthy thoughts and words" (410). Since there are voluntary and involuntary thoughts, that is, thoughts which come to us unsought and thoughts coming from our own will - for involuntary ones arise from previous sin, while voluntary ones are from our free will -therefore we can say that the voluntary thoughts are causes of the involuntary ones (411). The causes of thoughts are the passions, and the causes of passions are sinful acts (412).
In general we can say that the thoughts which come from the demons capture the nous and lead it to commit sin in thought and deed. And when this sin is repeated many times and the organism acquires a habit, passion comes into being. Then from the passions, which in a way are the wounds of the soul, come the corresponding evil thoughts. It is the same as with wounds of the body. Something causes the body to be wounded, and as a result the wound causes an irritation, whereupon the problem continues and increases further.
At many points in His teaching the Lord mentions that the evil thoughts come from within the heart. "Out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander" (Matt.15,19). Luke the Evangelist mentions that an argument arose among Christ's disciples "as to which of them would be greatest". "But when Jesus perceived the thought of their hearts, he took a child and put him by His side" (Lk.9,46f). When the Lord appeared after the Resurrection, he said to His disciples: "Why are you troubled? And why do questionings arise in your hearts?" (Lk.24,38). All these passages show that questionings come from within the heart of man. Indeed the nous is the first to be attacked by the thought, but then passions work in the heart, and through them the devil takes the opportunity to put his own thoughts into play. Therefore it is said that questionings come from within the heart.
The teaching of St. Diadochos of Photike is related to this. The heart produces good and evil thoughts. However, it does not produce evil thoughts by nature, but from the memory of evil, of that first sin which it committed and which led to the habit. The heart conceives most of its evil thoughts as a result of the evil of the demons. However, we feel that they arise from the heart. Man's nous, being highly responsive, makes its own the thoughts sown in it by the evil spirits. The same happens also with the flesh. Since the flesh delights in being flattered by deception and since there is a union between the soul and the body, the thoughts sown in the soul by the demons seem to come from the heart (413). The nous provides the nourishment for the heart. Whatever it has, good or bad, it transmits directly to the heart. Since most of us are inexperienced in this spiritual combat and since this transmission takes place very quickly, we feel that the thoughts are produced by the heart.
Aside from the devil and the passions, things in themselves engender thoughts. But, as St. Gregory of Sinai teaches, things in themselves give birth to simple thoughts, while suggestions of the devil engender evil thoughts (414). So matter is not bad; what is bad are the shameful desires within us, the passions in us and the provocation on the part of the demons. "Just as it is impossible to stop a watermill from turning" and grinding the wheat or tares that we throw into it, so it is with our mind; it is in constant motion. it depends on us whether we give it spiritual meditation or works of the flesh. Therefore when we are occupied with worldly concerns and matters of the flesh, and when we give ourselves over to pointless and useless conversation, "these base thoughts multiply in us" (415). So the use of the world and the being of the world are not bad, but what is bad is our own disposition, our own self-will.
Certainly aside from evil thoughts there are good thoughts, those coming from God. How can we distinguish these thoughts? Those of us who are beginners in the spiritual life should ask experienced spiritual fathers, and especially those who have the gift of distinguishing spirits. In any case, one general teaching is that when a thought suggests something to us and joy comes, it is a sign that the thought is from God. The thoughts of the devil are full of disturbance and dejection. St. Barsanuphios teaches: "When a thought suggests to you to do something according to the will of God, and you find in this matter joy, and at the same time sorrow which fights against it, know that this thought is from God...The thoughts which come from the devil are filled with disturbance and dejection, and they draw one after them secretly and subtly; for the enemies clothe themselves in sheepskins, that is, they instil thoughts which in appearance are right, but within are `ravening wolves'" (416). It must be noted that a thought is capable of evoking a joy which, however, comes from vanity and a self-indulgent heart. Therefore thoughts can be distinguished only by one who has tasted the grace of the Holy Spirit and has been cleansed from the passions which are found in the soul. Those who lack this experience should consult experienced spiritual fathers, because the devil suggests righteous thoughts, while he is unrighteous.
Now that we have pointed out what thoughts are and what causes give rise to them, we must look briefly at the different kinds of thoughts. Thoughts are analogous to the passions. For each passion there is a thought. St. Cassian of Rome divides them into eight and analyses at length the eight thoughts of evil. These are: "gluttony, unchastity, avarice, anger, dejection, listlessness, self-esteem and pride" (417).
St. Thalassios says that there are three basic thoughts: gluttony, self-esteem and avarice. All other impassioned thoughts follow in their wake (418). These three thoughts correspond to the three great general passions: self-indulgence, love of glory, and avarice or love of possessions, to which the temptations of Christ refer.
We must make mention of one great, disgraceful thought, that of blasphemy. St. John of the Ladder, recognising the wickedness and seriousness of thoughts of blasphemy, as well as the fact that they mainly attack those who are struggling in the spiritual life, devotes a whole chapter to describing them and presenting methods for ridding ourselves of these thoughts. He writes that the thought of blasphemy comes from pride. It attacks a man even during the Liturgy, even at the time of preparation for Holy Communion. It attacks the nous and distracts it from the words of the prayer. It stops many from praying and cuts many off from Communion; it causes the bodies of some to be worn away with grief. St. John of the Ladder advises us not to regard ourselves as the cause of thoughts of blasphemy. They are the demon's words intended to estrange us from God and His Church (419).
Yet evil thoughts are the beginning of the devil's warfare against us. A thought planted by the devil develops until the sin is committed and leads to passion. Therefore in what follows we shall try to see this development of evil thoughts in the light of the experience of the Holy Fathers.
St. Maximus teaches that the impassioned thoughts aroused by the passions lying hidden in the soul fight the nous and force it to give its assent to sin. When the nous has been overcome in this warfare "they lead it to sin in the mind; and when this has been done they induce it, captive as it is, to commit the sin in action". After the action the demons who have desolated the soul by means of these thoughts, retreat, but the spectre or idol of sin remains in the nous (420). Thus thoughts take the nous captive and lead it captive into sin. If the idol of sin is not driven away by intense and lasting repentance, it is a source of abnormalities in the spiritual organism.
This in general outline is the development of an intrusive thought and the course it takes. But we would do well also to see a few details about it, again as described by the Fathers.
The thought that has entered the soul's intelligence endeavours to capture the nous. To this end it prompts a feeling of the pleasure to be afforded by one or another passion which is in the soul. This stage is called temptation and is not to be reckoned as sin (421). Prolonged delectation afforded by the passion attracts the attention of the nous (422). If the nous does not tear itself away from the suggested delights, it finds itself attracted, favourable conversation with them begins, coupling follows, and it comes to assent. The increasing pleasure captures the whole nous, and the will as well. Thus the person's resistance becomes weak. Then the sin is committed. When the captures are repeated, the habit of a passion is formed, "and then all man's natural forces are at its service" (423). The presence and prolongation of pleasure are very important for the capture and activation of passion. Therefore the Fathers advise mortifying the pleasure as far as possible, or better, its transformation, when it captures the person's nous. Abba Dorotheos says that whenever passionate desires reappear in the soul of those who put up a fight, they are immediately rejected (424).
Hesychios writes about the mingling and uniting of the soul's thoughts with the provocation of the demon through fantasy: "...its thoughts become entwined in the fantasy provoked by the devil", and so it comes to assent and to action (425). Fantasy plays an important role, especially in cases where the object or person is far from us. But also when the person or object is seen, that is, when it is linked with the senses, then too fantasy magnifies things and increases their beauty in order to capture the nous and lead it to consent. From this point of view we can say that impassioned thoughts blur and confuse the nous, fill it with impure images and carry it "unwillingly and forcefully towards sinful acts" (426).
It seems that a man's freedom gives its consent not only at the time when it receives the temptation, the proposal from the demonic thought, but also beforehand, when, with freedom's consent, the eye and the ear of the soul are darkened. As Philotheos of Sinai teaches, the reason why a person looks on things adulterously is that "the inner eye has become adulterous and darkened" and the reason for wanting to hear about foul things is that "our soul's ears have listened to what the foul demons inside us have whispered to us" (427). If a person is corrupted inwardly, the eye of his heart is defiled and then his outward bodily senses are also corrupted. That is why man's struggle must first be carried on inwardly.
Likewise when a person keeps thoughts within him and elaborates them, pleasure arises and the nous comes to assent and action. "As eggs warmed in dung hatch out, so unconfessed evil thoughts hatch evil actions" (428).
What has been said shows clearly the consequences of prolonged and elaborated thoughts. In the next section we shall present these consequences.