Looking up a solution isn't a sin. The only sin is not understanding that solution when you do.
A common refrain in reviews of The Witness is the plea to solve each puzzle on your own, to not ask for help or look up solutions, that the game is designed to teach you things in ordered steps and that it is important not to skip a step. While, yes, this is true, that doesn't mean those steps are easy. What will inevitably happen is that you'll solve a series of simple puzzles, and then you'll try to solve the next puzzle in the exact same way that you solved the previous puzzles, only this time your solution won't work. You've done something wrong. You've misunderstood the concept. Time to go back and reanalyze your work.
This is where an "easy" puzzle can become hard, when we've trained ourselves to think one way only to realize that that is the wrong way of thinking. Unlearning a lesson is harder than learning one, and when we're stumped like this, the truth is that it's okay to ask for help. You're not committing any sin against the game by asking for a hint or even for just outright looking up the solution. The only sin is not understanding that solution.
I was stumped by the Bunker/Greenhouse puzzles (don't worry, there are no spoilers here) and by one in particular that seemed impossible given the rules as I understood them. A friend came in to help, got fed up, and looked up the solution, which made no goddamn sense to her. My curiosity was piqued, so I looked at the solution too, which made no goddamn sense to me. But it worked. I completed the puzzle. The next one unlocked for me so that I could move on if I wanted to, but I didn't move on. I had my answer, but I still didn't understand the question, so I stayed at this puzzle, poking and prodding it until I found my missing piece.
It's a good thing that I stayed and reverse-engineered the question from the answer because every subsequent puzzle in the Bunker/Greenhouse branched out from that one puzzle, building upon its trick. If I had just moved on I wouldn't have been able to solve the next puzzle. The solution wasn't really the answer that I needed, it was meaningless without context. The real point of the puzzle was to teach me a new way of looking at things, to open my mind to a new methodology.
That's what The Witness is all about. It's not really a game about solving puzzles. It's about understanding the process by which we learn new things. The Witness teaches us how to learn. The puzzles are just a conduit for this real lesson, a fun way of expressing this abstract idea through the logical language of programming code.
If you look up a solution and then just move on, you're committing the greatest sin in the world of the The Witness. You're taking knowledge for granted.
You're not learning from the game, and you're not understanding how a solution came to be. Your knowledge is unearned, and the rest of the game becomes harder as it builds on a concept that you don't understand. If you take the time to reverse engineer the question from the solution, then no sin is committed because you’re still participating in the act of learning. Sometimes we need help, and there's no shame in asking for help, just as long as we use that help to further our own understanding:
An understanding of our skills tells us what we’re good at doing. An understanding of our limits allows us to know what we don't know. An understanding of the process of learning lets us see how every concept is made up of smaller ideas. Most importantly, we need to understand that every solution is not an answer, and it's not an end point. Every solution is really just another piece of a larger puzzle, every idea a piece of a larger concept, every island a part of a larger world, into infinity. The puzzles never end, they just keep getting bigger, and we’ll be overwhelmed if we don’t learn these basics.
That's why it's okay to look up a solution. You can do it once, you can do it twice, you can do it a hundred times, but you can’t do it forever. Eventually, you'll encounter a puzzle or a problem or a question that you'll have to solve yourself. You won't be able to ask for help. The Witness wants to prepare you for this moment, both within its world and the real world, it wants to teach you how to break down impossible tasks into manageable chunks. It's an education in critical thinking.
The problems/puzzles/questions that we face in life may be more three dimensional than those in The Witness, but the process of solving them is no different. Learn the underlying concepts first, then solve the problem in steps because every problem is just a series of smaller issues, every question is just a series of smaller queries, and every puzzle is just a series of smaller puzzles.
Life is puzzles all the way up and down, so it’s okay to ask for help every now and then. You’re going to need it. Just don’t fool yourself into thinking that you get it when you don’t -- because that’s no help for anyone.