When Dorothy was a little girl, she was fascinated by her goldfish. Her father explained to her that fish swim by quickly wagging their tails to propel themselves through the water. Without hesitation, little Dorothy responded, "Yes, Daddy, and fish swim backwards by wagging their heads." (Laughter) In her mind, it was a fact as true as any other. Fish swim backwards by wagging their heads. She believed it. Our lives are full of fish swimming backwards. We make assumptions and faulty leaps of logic. We harbor bias. We know that we are right, and they are wrong. We fear the worst. We strive for unattainable perfection. We tell ourselves what we can and cannot do. In our minds, fish swim by in reverse frantically wagging their heads and we don't even notice them. I'm going to tell you five facts about myself. One fact is not true. One: I graduated from Harvard at 19 with an honors degree in mathematics. Two: I currently run a construction company in Orlando. Three: I starred on a television sitcom. Four: I lost my sight to a rare genetic eye disease. Five: I served as a law clerk to two US Supreme Court justices. Which fact is not true? Actually, they're all true. Yeah. They're all true. (Applause) At this point, most people really only care about the television show. (Laughter) I know this from experience. OK, so the show was NBC's "Saved by the Bell: The New Class." And I played Weasel Wyzell, who was the sort of dorky, nerdy character on the show, which made it a very major acting challenge for me as a 13-year-old boy. (Laughter) Now, did you struggle with number four, my blindness? Why is that? We make assumptions about so-called disabilities. As a blind man, I confront others' incorrect assumptions about my abilities every day. My point today is not about my blindness, however. It's about my vision. Going blind taught me to live my life eyes wide open. It taught me to spot those backwards-swimming fish that our minds create. Going blind cast them into focus. What does it feel like to see? It's immediate and passive. You open your eyes and there's the world. Seeing is believing. Sight is truth. Right? Well, that's what I thought. Then, from age 12 to 25, my retinas progressively deteriorated. My sight became an increasingly bizarre carnival funhouse hall of mirrors and illusions. The salesperson I was relieved to spot in a store was really a mannequin. Reaching down to wash my hands, I suddenly saw it was a urinal I was touching, not a sink, when my fingers felt its true shape. A friend described the photograph in my hand, and only then I could see the image depicted. Objects appeared, morphed and disappeared in my reality. It was difficult and exhausting to see. I pieced together fragmented, transitory images, consciously analyzed the clues, searched for some logic in my crumbling kaleidoscope, until I saw nothing at all. I learned that what we see is not universal truth. It is not objective reality. What we see is a unique, personal, virtual reality that is masterfully constructed by our brain. Let me explain with a bit of amateur neuroscience. Your visual cortex takes up about 30 percent of your brain. That's compared to approximately eight percent for touch and two to three percent for hearing. Every second, your eyes can send your visual cortex as many as two billion pieces of information. The rest of your body can send your brain only an additional billion. So sight is one third of your brain by volume and can claim about two thirds of your brain's processing resources. It's no surprise then that the illusion of sight is so compelling. But make no mistake about it: sight is an illusion. Here's where it gets interesting. To create the experience of sight, your brain references your conceptual understanding of the world, other knowledge, your memories, opinions, emotions, mental attention. All of these things and far more are linked in your brain to your sight. These linkages work both ways, and usually occur subconsciously. So for example, what you see impacts how you feel, and the way you feel can literally change what you see. Numerous studies demonstrate this. If you are asked to estimate the walking speed of a man in a video, for example, your answer will be different if you're told to think about cheetahs or turtles. A hill appears steeper if you've just exercised, and a landmark appears farther away if you're wearing a heavy backpack. We have arrived at a fundamental contradiction. What you see is a complex mental construction of your own making, but you experience it passively as a direct representation of the world around you. You create your own reality, and you believe it. I believed mine until it broke apart. The deterioration of my eyes shattered the illusion. You see, sight is just one way we shape our reality. We create our own realities in many other ways. Let's take fear as just one example. Your fears distort your reality. Under the warped logic of fear, anything is better than the uncertain. Fear fills the void at all costs, passing off what you dread for what you know, offering up the worst in place of the ambiguous, substituting assumption for reason. Psychologists have a great term for it: awfulizing. (Laughter) Right? Fear replaces the unknown with the awful. Now, fear is self-realizing. When you face the greatest need to look outside yourself and think critically, fear beats a retreat deep inside your mind, shrinking and distorting your view, drowning your capacity for critical thought with a flood of disruptive emotions. When you face a compelling opportunity to take action, fear lulls you into inaction, enticing you to passively watch its prophecies fulfill themselves. When I was diagnosed with my blinding disease, I knew blindness would ruin my life. Blindness was a death sentence for my independence. It was the end of achievement for me. Blindness meant I would live an unremarkable life, small and sad, and likely alone. I knew it. This was a fiction born of my fears, but I believed it. It was a lie, but it was my reality, just like those backwards-swimming fish in little Dorothy's mind. If I had not confronted the reality of my fear, I would have lived it. I am certain of that. So how do you live your life eyes wide open? It is a learned discipline. It can be taught. It can be practiced. I will summarize very briefly. Hold yourself accountable for every moment, every thought, every detail. See beyond your fears. Recognize your assumptions. Harness your internal strength. Silence your internal critic. Correct your misconceptions about luck and about success. Accept your strengths and your weaknesses, and understand the difference. Open your hearts to your bountiful blessings. Your fears, your critics, your heroes, your villains -- they are your excuses, rationalizations, shortcuts, justifications, your surrender. They are fictions you perceive as reality. Choose to see through them. Choose to let them go. You are the creator of your reality. With that empowerment comes complete responsibility. I chose to step out of fear's tunnel into terrain uncharted and undefined. I chose to build there a blessed life. Far from alone, I share my beautiful life with Dorothy, my beautiful wife, with our triplets, whom we call the Tripskys, and with the latest addition to the family, sweet baby Clementine. What do you fear? What lies do you tell yourself? How do you embellish your truth and write your own fictions? What reality are you creating for yourself? In your career and personal life, in your relationships, and in your heart and soul, your backwards-swimming fish do you great harm. They exact a toll in missed opportunities and unrealized potential, and they engender insecurity and distrust where you seek fulfillment and connection. I urge you to search them out. Helen Keller said that the only thing worse than being blind is having sight but no vision. For me, going blind was a profound blessing, because blindness gave me vision. I hope you can see what I see. Thank you. (Applause) Bruno Giussani: Isaac, before you leave the stage, just a question. This is an audience of entrepreneurs, of doers, of innovators. You are a CEO of a company down in Florida, and many are probably wondering, how is it to be a blind CEO? What kind of specific challenges do you have, and how do you overcome them? Isaac Lidsky: Well, the biggest challenge became a blessing. I don't get visual feedback from people. (Laughter) BG: What's that noise there? IL: Yeah. So, for example, in my leadership team meetings, I don't see facial expressions or gestures. I've learned to solicit a lot more verbal feedback. I basically force people to tell me what they think. And in this respect, it's become, like I said, a real blessing for me personally and for my company, because we communicate at a far deeper level, we avoid ambiguities, and most important, my team knows that what they think truly matters. BG: Isaac, thank you for coming to TED. IL: Thank you, Bruno. (Applause)