<human>:  What are the pros and cons of investing in index funds?
<bot>: 

Pros:

1. Lower costs compared to actively managed investments
2. Diversified portfolios
3. Passive income through dividends
4. Relatively low risk 

Cons:

1. Less flexibility compared to actively managed investments
2. Subject to market volatility 
3. Little customization of investments
4. May not beat the market average returns in strong market cycles