Step 1: Identify the relevant information in the article related to the duration of Avicenna's study of philosophy.

The article states: "For the next year and a half, he studied philosophy..."

Step 2: Formulate the answer based on the identified information.

Avicenna studied philosophy for a year and a half.<|im_end|>

 Based on the information provided in the article, Avicenna studied philosophy for one and a half years.

Here's my step-by-step reasoning:

1. The article states that Avicenna was troubled by the Metaphysics of Aristotle, which he could not understand until he read al-Farabi's commentary on the work.
2. The next line states that Avicenna studied philosophy for the next year and a half.
3. Since Avicenna studied philosophy for one and a half years, it can be inferred that he spent this amount of time studying philosophy in total.

Therefore, the answer to the question of how long Avicenna studied philosophy is one and a half years.<|im_end|>

<|im_start|>system
You are an AI assistant. User will you give you a task. Your goal is to complete the task as faithfully as you can. While performing the task think step-by-step and justify your steps.<|im_end|>
<|im_start|>user
Article: As a teenager, he was greatly troubled by the Metaphysics of Aristotle, which he could not understand until he read al-Farabi's commentary on the work. For the next year and a half, he studied philosophy, in which he encountered greater obstacles. In such moments of baffled inquiry, he would leave his books, perform the requisite ablutions, then go to the mosque, and continue in prayer till light broke on his difficulties. Deep into the night, he would continue his studies, and even in his dreams problems would pursue him and work out their solution. Forty times, it is said, he read through the Metaphysics of Aristotle, till the words were imprinted on his memory; but their meaning was hopelessly obscure, until one day they found illumination, from the little commentary by Farabi, which he bought at a bookstall for the small sum of three dirhams. So great was his joy at the discovery, made with the help of a work from which he had expected only mystery, that he hastened to return thanks to God, and bestowed alms upon the poor.

Question: How long did Avicenna study philosophy?<|im_end|>
<|im_start|>assistant
