Final answer:
The key takeaway is to critically examine cognitive biases and engage in reflective thinking to overcome them, which is essential for a philosophy student's development of critical thinking skills.
Step-by-step explanation:
The best theme to take away from the perceptual illusions TED talk can be understood as the critical examination of our own cognitive biases and the need for reflective thinking. Our perception does not present a full picture of the world, but rather a summary that highlights significant events based on their relevance to our survival. Therefore, one must always be skeptical of immediate perceptions and must engage in effortful, reflective thinking to identify and overcome these biases. This is crucial for developing critical thinking skills, particularly relevant to a philosophy student who must scrutinize not only the information received but also the processes by which they perceive and interpret that information.