Was Isaac forced to repeat his mistakes over and over (the definition of insanity.)

Why didn't Isaac learn earlier in life that what he was doing would get him into trouble?

Isaac was neither insane nor particularly amoral but he was driven by a huge desire to be financially successful and physically was willing to work very hard to attain his goals but was always looking for a way to get there faster. As we see so often in the news these days very successful people who are financially rather well off are frequently caught embezzling funds over which they have some control and to an outsider it is very hard to understand why they did it. Isaac's constant pushing from his mother to go for the opportunity was also a factor and he was always nagged by the Clever/Stupid line that she said to him a bit too frequently.

I don't know that I would consider him 'forced' to repeat his mistakes over and over again. He clearly had choices, and would sometimes demonstrate his independence (albeit for a short time). But he clearly demonstrates why repeated unfulfilling actions all but define the word insanity!
How much of ones behavior is nature? How much is nurture? How very much we are all influenced and shaped by our closest caregivers and family members to varying degrees.
Isaac wanted so much to please his mother; perhaps he wanted to get her into the house of her dreams for her sake, to make himself look bigger in her eyes, to rescue her from her past, or maybe (especially) to just shut her up!

I don't think Isaac was forced to repeat his mistakes, and I don't think he was insane. Rather, I think his actions and reactions are a result of his nature. I think he was constantly trying to find himself, seeking the courage and strength to attain honor in the difficult world he lived in. His mother's constant advice to be clever, not stupid plagued him--he wanted so much to please her.

Isaac may have not been insane just obsessed. Isaac was under the delusion that wealth is the ultimate goal. With wealth/money he would be able to buy his mother a house. What she most desired from him. He would be a Clever not a Stupid and at what cost. This novel seemed brimming with metaphores about greed and wealth. A parable with religious overtones.

I don't think anyone forced him to do anything. I didn't consider him insane either. I did find his repeated stupidity reckless, but perhaps those are the choices that a young, uneducated immigrant would make in his attempts to succeed in another environment. In some ways he was quite street savvy, but in others, like his relationship with Hugo, he seemed like he just had a target on his back. This made him quite the unconventional main character in the book.

He wasn't forced, though eventually I wished I could reach in and shake him at times! I believe he did learn just a little from each setback, though he justified to himself why this action would work and how this situation was different than the past one. Sounds a bit like myself as a young 20-something trying to navigate independently, and I didn't have near the challenges that Isaac had.

Not really "forced" per se, but I think it was inherent in his nature to keep going toward the same goal irregardless of the circumstances.

I agree with everyone who said he wasn't forced and I, too, was very frustrated with him at time. But as the mother of a 30 something who never seems to learn from his mistakes I also felt bad for him. Life is just more difficult for some people

No, Isaac was not forced. Manipulated often. Stupid about many things. But not forced. Guilt is a strong motivator and Isaac's mother was a master of making him feel guilty. His intentions were usually good but he didn't seem to know the 'right' way to do things and often made a huge mess of his good intentions. He had great talents but did not follow through with plans that would help him achieve his goals. His imagination/naivety and lack of education got him in trouble many times.

Isaac was a free actor and was not predestined to follow a particular path or to live his life in any particular way. That said, however, Isaac was influenced by the people around him, his station in life and the forces at play in his community, his country and the world at large. First among these influences were Gitelle and Abel. Gitelle's pain deeply burdened Isaac, and his response to his mother's suffering was a major motivator for Isaac's actions. Notwithstanding his periodic fits of rage, Isaac had a tenderness and a trustfulness about him which were traits that Isaac saw in his father. I attribute Isaac's misplaced trust in Hugo and forgiveness of Magnus, which led to what might be characterized as mistakes, to the goodness which Isaac took from Abel. As for Isaac's rebelliousness in school and aggression against Magnus, he was acting out in response to the discrimination and prejudice to which he and his family were subjected as poor Jewish immigrants. In short, Isaac's mistakes were not inevitable but certainly understandable.

Unlike some of the other readers, I found Isaac to be a compelling character and a good person. He was a good son, a good friend, loyal, honest and hard working. He succeeded against great odds and lived a life that, taken as a whole, I respect. I applaud the author for creating such a strong protagonist who was complex, believable and worthy of the story of which he was a part.