In Philadelphia there lives a gentle, gracious, grey-haired man, by now in his late-90s, whom Elaine and I have had the pleasure of meeting several times and who is one of the most lovely people we have ever known. Many people have reason to be thankful to him, because his work has transformed many lives, rescuing people from depression and other debilitating psychological states.

His name is Aaron T. Beck and he is the founder of one of the most effective forms of psychotherapy yet devised: Cognitive Behavioural Therapy. He discovered it through his work at the depression research clinic he founded in the University of Pennsylvania. He began to detect a pattern among his patients. It had to do with the way they interpreted events. They did so in negative ways that were damaging to their self-respect, and fatalistic. It was as if they had thought themselves into a condition that one of Beck’s most brilliant disciples, Martin Seligman, was later to call “learned helplessness.” Essentially they kept telling themselves, “I am a failure. Nothing I try ever succeeds. I am useless. Things will never change.”

They had these thoughts automatically. They were their default reaction to anything that went wrong in their lives. But Beck found that if they became conscious of these thoughts, saw how unjustified they were, and developed different and more realistic thought patterns, they could, in effect, cure themselves. This also turns out to be a revelatory way of understanding the key episode of our parsha, namely the story of the spies.

Recall what happened. Moses sent twelve men to spy out the land. The men were leaders, princes of their tribes, people of distinction. Yet ten of them came back with a demoralising report. The land, they said, is indeed good. It does flow with milk and honey. But the people are strong. The cities are large and well fortified. Caleb tried to calm the people. “We can do it.” But the ten said that it could not be done. The people are stronger than we are. They are giants. We are grasshoppers.

And so the terrible event happened. The people lost heart. “If only,” they said, “we had died in Egypt. Let us choose a leader and go back.” God became angry. Moses pleaded for mercy. God relented, but insisted that none of that generation, with the sole exceptions of the two dissenting spies, Caleb and Joshua, would live to enter the land. The people would stay in the wilderness for forty years, and there they would die. Their children would eventually inherit what might have been theirs had they only had faith.

Essential to understanding this passage is the fact that the report of the ten spies was utterly unfounded. Only much later, in the book of Joshua, when Joshua himself sent spies, did they learn from the woman who sheltered them, Rahab, what actually happened when the inhabitants of the land heard that the Israelites were coming:

“I know that the Lord has given you the land, and that dread of you has fallen on us, and that all the inhabitants of the land melt in fear before you … As soon as we heard it, our hearts melted, and there was no courage left in any of us because of you.” (Josh. 2:9-11)

The spies were terrified of the Canaanites, and entirely failed to realise that the Canaanites were terrified of them. How could they make such a profound mistake? For this we turn to Cognitive Behavioural Therapy, and to some of the types of distorted thinking identified by Beck’s student, David Burns.

One is all-or-nothing thinking. Everything is either black or white, good or bad, easy or impossible. That was the spies’ verdict on the possibility of conquest. It couldn’t be done. There was no room for shading, nuance, complexity. They could have said, “It will be difficult, we will need courage and skill, but with God’s help we will prevail.” But they did not. Their thinking was a polarised either/or.

Another is negative filtering. We discount the positives as being insignificant, and focus almost exclusively on the negatives. The spies began by noting the positives: “The land is good. Look at its fruit.” Then came the “but”: the long string of negatives, drowning out the good news and leaving an overwhelmingly negative impression.

A third is catastrophising, expecting disaster to strike, no matter what. That is what the people did when they said, “Why is the Lord bringing us to this land only to let us die by the sword? Our wives and children will be taken as plunder.”

A fourth is mind-reading. We assume we know what other people are thinking, when usually we are completely wrong because we are jumping to conclusions about them based on our own feelings, not theirs. That is what the spies did when they said, “We seemed like grasshoppers in our own eyes, and so we seemed to them.” They had no way of knowing how they appeared to the people of the land, but they attributed to them, mistakenly, a sentiment based on their own subjective fears.

A fifth is inability to disconfirm. You reject any evidence or argument that might contradict your negative thoughts. The spies heard the counter-argument of Caleb but dismissed it. They had decided that any attempt to conquer the land would fail, and they were simply not open to any other interpretation of the facts.

A sixth is emotional reasoning: letting your feelings, rather than careful deliberation, dictate your thinking. A key example is the interpretation the spies placed on the fact that the cities were “fortified and very large” (Num. 13:28), or “with walls up to the sky” (Deut. 1:28). They did not stop to think that people who need high city walls to protect them are in fact fearful. Had they stopped to think, they might have realised that the Canaanites were not confident, not giants, not invulnerable. But they let their emotions substitute for thought.

A seventh is blame. We accuse someone else of being responsible for our predicament instead of accepting responsibility ourselves. This is what the people did in the wake of the spies’ report. “They grumbled against Moses and Aaron” (Num. 14:1), as if to say, “It is all your fault. If only you had let us stay in Egypt!” People who blame others have already begun down the road to “learned helplessness.” They see themselves as powerless to change. They are the passive victims of forces beyond their control.

Applying cognitive behavioural therapy to the story of the spies lets us see how that ancient event might be relevant to us, here, now. It is very easy to fall into these and other forms of cognitive distortion, and the result can be depression and despair –dangerous states of mind that need immediate medical or therapeutic attention.

What I find profoundly moving is the therapy the Torah itself prescribes. I have pointed out elsewhere that the end of the parsha – the paragraph dealing with tzitzit – is connected to the episode of the spies by two keywords, ure-item, “you shall see” (Num. 13:18; 15:39), and the verb latur, (Num. 13:2, 16, 17, 25, 32; 15:39). The key sentence is the one that says about the thread of blue in the tzitzit, that “when you see it, you will remember all the commandments of the Lord and do them, and not follow after your own heart and your own eyes” (Num. 15:39).

Note the strange order of the parts of the body. Normally we would expect it to be the other way around: as Rashi says in his commentary to the verse, “The eye sees and the heart desires.” First we see, then we feel. But in fact the Torah reverses the order, thus anticipating the very point Cognitive Behavioural Therapy makes, which is that often our feelings distort our perception. We see what we fear – and often what we think we see is not there at all. Hence Roosevelt’s famous words in his first Inaugural Address – stunningly relevant to the story of the spies: “the only thing we have to fear is…fear itself — nameless, unreasoning, unjustified terror which paralyses needed efforts to convert retreat into advance.”

The blue thread in the tzitzit, says the Talmud (Sotah 17a), is there to remind us of the sea, the sky, and God’s throne of glory. Techelet, the blue itself, was in the ancient world the mark of royalty. Thus the tzitzit as itself a form of cognitive behavioural therapy, saying: “Do not be afraid. God is with you. And do not give way to your emotions, because you are royalty: you are children of the King.”

Hence the life-changing idea: never let negative emotions distort your perceptions. You are not a grasshopper. Those who oppose you are not giants. To see the world as it is, not as you are afraid it might be, let faith banish fear.